2026
|
Gimpel, T.; Büttgen, N.; Prodan, L.; Tsurkan, V.; Tsirlin, A. A.; Nakamura, H.; Kézsmárki, I. Magnetic symmetry and hyperfine fields of V_4 tetrahedral clusters in the multiferroic lacunar spinel GeV4S8 Journal Article Phys. Rev. B 114, 154418 (2026), datadoi: (10.5281/zenodo.20604906). @article{xn3r-b7g6,
title = {Magnetic symmetry and hyperfine fields of V_4 tetrahedral clusters in the multiferroic lacunar spinel GeV_{4}S_{8}},
author = {T. Gimpel and N. Büttgen and L. Prodan and V. Tsurkan and A. A. Tsirlin and H. Nakamura and I. Kézsmárki},
url = {https://link.aps.org/doi/10.1103/xn3r-b7g6},
doi = {10.1103/xn3r-b7g6},
year = {2026},
date = {2026-09-18},
urldate = {2026-09-01},
journal = {Phys. Rev. B},
volume = {114},
number = {15},
pages = {154418},
abstract = {We use 51V nuclear magnetic resonance (NMR) spectroscopy to investigate the magnetic ground state of the lacunar spinel GeV4S8, which undergoes a structural distortion at 𝑇JT≈30K followed by an antiferromagnetic (AFM) ordering at 𝑇𝑁≈15K. According to our zero- and finite-field NMR data, the four V-sites of V4 clusters become magnetically inequivalent in the AFM state: Two of them share the same internal field, while the other two sites are characterized by different internal fields. The angular dependence of the 51V NMR lines, upon rotation of an external magnetic field about the pseudocubic [110] and [100] axes, reveals that the internal fields are either parallel to the orthorhombic 𝑎 axis at all four V-sites of the V4 tetrahedra, or they form an orthogonal pattern, where two V-sites have internal field along the 𝑎 axis and the other two along the 𝑏 axis. Based on these results, further supported by the observation of distinct spin-echo modulations of the inequivalent V-sites, we conclude that the magnetic space group of the AFM state is 𝑃𝑏𝑚𝑛21 or 𝑃𝑚𝑛′2′1.},
note = {datadoi: (10.5281/zenodo.20604906)},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We use 51V nuclear magnetic resonance (NMR) spectroscopy to investigate the magnetic ground state of the lacunar spinel GeV4S8, which undergoes a structural distortion at 𝑇JT≈30K followed by an antiferromagnetic (AFM) ordering at 𝑇𝑁≈15K. According to our zero- and finite-field NMR data, the four V-sites of V4 clusters become magnetically inequivalent in the AFM state: Two of them share the same internal field, while the other two sites are characterized by different internal fields. The angular dependence of the 51V NMR lines, upon rotation of an external magnetic field about the pseudocubic [110] and [100] axes, reveals that the internal fields are either parallel to the orthorhombic 𝑎 axis at all four V-sites of the V4 tetrahedra, or they form an orthogonal pattern, where two V-sites have internal field along the 𝑎 axis and the other two along the 𝑏 axis. Based on these results, further supported by the observation of distinct spin-echo modulations of the inequivalent V-sites, we conclude that the magnetic space group of the AFM state is 𝑃𝑏𝑚𝑛21 or 𝑃𝑚𝑛′2′1. |  |
Wang, Y.; Wu, Z.; Bhupendra, K. C.; Zhang, D.; Wang, L.; Khare, S. V.; Prodan, L.; Tsurkan, V. Pressure-induced electronic delocalization and superconductivity in GaNb4Se8 Journal Article Phys. Rev. B 114, 175107 (2026). @article{8b8c-2wm3,
title = {Pressure-induced electronic delocalization and superconductivity in GaNb_{4}Se_{8}},
author = {Y. Wang and Z. Wu and K. C. Bhupendra and D. Zhang and L. Wang and S. V. Khare and L. Prodan and V. Tsurkan},
url = {https://link.aps.org/doi/10.1103/8b8c-2wm3},
doi = {10.1103/8b8c-2wm3},
year = {2026},
date = {2026-09-04},
urldate = {2026-09-01},
journal = {Phys. Rev. B},
volume = {114},
number = {17},
pages = {175107},
publisher = {American Physical Society},
abstract = {Understanding how electronic transport evolves from localized to itinerant regimes in correlated cluster solids remains an important challenge in condensed-matter physics. Here, we investigate the pressure-dependent transport properties of the lacunar spinel GaNb4Se8, a cluster Mott insulator at ambient conditions. At ambient pressure, the resistivity follows Efros-Shklovskii variable-range hopping, indicating Coulomb gap–controlled carrier localization. A pressure-induced electronic delocalization process begins at low pressures (∼5 GPa), as evidenced by the continuous suppression of room-temperature resistance. Upon further compression, the system undergoes a broad insulator-to-metal-like crossover in low-temperature transport, culminating in a fully metallic-like ground state at ∼17–18 GPa. In contrast, the crystallographic transition from the cubic phase to the monoclinic 𝐶2 phase starts at ∼20 GPa and ends near ∼32 GPa, demonstrating that the pressure-induced electronic evolution is completed before the onset of long-range structural symmetry breaking. At higher pressures, superconductivity (with a superconducting coherence length ξ(0) ≈ 80–90 Å) emerges from a pressure-induced metallic-like regime. These results establish GaNb4Se8 as a platform for studying correlation-driven evolution of electronic transport in cluster-based solids.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Understanding how electronic transport evolves from localized to itinerant regimes in correlated cluster solids remains an important challenge in condensed-matter physics. Here, we investigate the pressure-dependent transport properties of the lacunar spinel GaNb4Se8, a cluster Mott insulator at ambient conditions. At ambient pressure, the resistivity follows Efros-Shklovskii variable-range hopping, indicating Coulomb gap–controlled carrier localization. A pressure-induced electronic delocalization process begins at low pressures (∼5 GPa), as evidenced by the continuous suppression of room-temperature resistance. Upon further compression, the system undergoes a broad insulator-to-metal-like crossover in low-temperature transport, culminating in a fully metallic-like ground state at ∼17–18 GPa. In contrast, the crystallographic transition from the cubic phase to the monoclinic 𝐶2 phase starts at ∼20 GPa and ends near ∼32 GPa, demonstrating that the pressure-induced electronic evolution is completed before the onset of long-range structural symmetry breaking. At higher pressures, superconductivity (with a superconducting coherence length ξ(0) ≈ 80–90 Å) emerges from a pressure-induced metallic-like regime. These results establish GaNb4Se8 as a platform for studying correlation-driven evolution of electronic transport in cluster-based solids. | |
Fazlizhanov, I.; Seidov, Z. Y.; von Nidda, H. -A. Krug; Krellner, C.; Klingner, C.; Pedrero, L.; Lausberg, S.; Brando, M.; Geibel, C.; Steglich, F.; Sichelschmidt, J. Evolution of low-temperature electron spin resonance in Y(Rh0.73Co0.27)2Si2 upon entering ferromagnetic order Journal Article Phys. Rev. B 114, 115117 (2026). @article{fazlizhanovEvolutionLowtemperatureElectron2026,
title = {Evolution of low-temperature electron spin resonance in Y(Rh_{0.73}Co_{0.27})_{2}Si_{2} upon entering ferromagnetic order},
author = {I. Fazlizhanov and Z. Y. Seidov and H. -A. Krug von Nidda and C. Krellner and C. Klingner and L. Pedrero and S. Lausberg and M. Brando and C. Geibel and F. Steglich and J. Sichelschmidt},
url = {https://link.aps.org/doi/10.1103/csyd-6npb},
doi = {10.1103/csyd-6npb},
year = {2026},
date = {2026-08-17},
urldate = {2026-08-01},
journal = {Phys. Rev. B},
volume = {114},
number = {11},
pages = {115117},
publisher = {American Physical Society},
abstract = {We report electron spin resonance (ESR) experiments conducted on oriented powder of the heavy-fermion ferromagnet Yb(Rh0.73Co0.27)2Si2 in the temperature range 0.75≤𝑇≤4K, which includes the transition between the paramagnetic and ferromagnetic ordered phases below the Curie temperature 𝑇C=1.3K. The ESR measurements were performed using a home-built 3He cryostat at 𝑋-band frequencies. In the ferromagnetic ordered phase the ESR spectra of Yb(Rh0.73Co0.27)2Si2 are split into two lines. While the resonance in the paramagnetic phase features an easy-plane crystalline electric field induced anisotropy of the 𝑔 tensor perpendicular to the 𝑐 axis of the tetragonal crystal structure, the split lines in the ordered phase can be related to ferromagnetic resonance modes with a uniaxial exchange-type anisotropy along the 𝑐 axis. The corresponding effective anisotropy field can be determined.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report electron spin resonance (ESR) experiments conducted on oriented powder of the heavy-fermion ferromagnet Yb(Rh0.73Co0.27)2Si2 in the temperature range 0.75≤𝑇≤4K, which includes the transition between the paramagnetic and ferromagnetic ordered phases below the Curie temperature 𝑇C=1.3K. The ESR measurements were performed using a home-built 3He cryostat at 𝑋-band frequencies. In the ferromagnetic ordered phase the ESR spectra of Yb(Rh0.73Co0.27)2Si2 are split into two lines. While the resonance in the paramagnetic phase features an easy-plane crystalline electric field induced anisotropy of the 𝑔 tensor perpendicular to the 𝑐 axis of the tetragonal crystal structure, the split lines in the ordered phase can be related to ferromagnetic resonance modes with a uniaxial exchange-type anisotropy along the 𝑐 axis. The corresponding effective anisotropy field can be determined. | |
Gippius, A. A.; Zhurenko, S. V.; Tkachev, A. V.; Gunbin, A. V.; Büttgen, N.; Schaedler, M.; Silkin, I. G.; Morozov, I. V.; Bogach, A. V.; Sobolev, A. V.; Presniakov, I. A.; Moskvin, A. S. Short-range helical magnetic order in FeP1-xAsx (x = 0.33 and 0.5) Journal Article J. Magn. Magn. Mater. 651, 174177 (2026). @article{GIPPIUS2026174177,
title = {Short-range helical magnetic order in FeP_{1-x}As_{x} (x = 0.33 and 0.5)},
author = {A. A. Gippius and S. V. Zhurenko and A. V. Tkachev and A. V. Gunbin and N. Büttgen and M. Schaedler and I. G. Silkin and I. V. Morozov and A. V. Bogach and A. V. Sobolev and I. A. Presniakov and A. S. Moskvin},
url = {https://www.sciencedirect.com/science/article/pii/S0304885326003689},
doi = {10.1016/j.jmmm.2026.174177},
year = {2026},
date = {2026-08-01},
urldate = {2026-08-01},
journal = {J. Magn. Magn. Mater.},
volume = {651},
pages = {174177},
abstract = {Although the FeP1-xAsx solid solution compounds are isostructural with the binary helimagnets FeP and FeAs with MnP-type structure (sp. gr. Pnma) of the B31 family, their magnetic structure remained unclear. We studied two members of this family (x = 0.33 and 0.5) via microscopic site-selective techniques such as Mössbauer and NMR spectroscopy. Our results indicate that the helimagnetic nature of the ground state is preserved, but undergoes significant modifications. In particular, its ordering range seems to become drastically shorter, so that the local fields on the non-magnetic phosphorus atoms decrease several times compared to those in FeP, and even local fields on iron slightly decrease compared to FeP and FeAs. The ordering temperature for these fragmented structures is suppressed down to 20–30 K, which is significantly lower than the TN values for FeP and FeAs. Additionally, both compounds demonstrate higher sustainability to the external field than the parent compound FeP.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Although the FeP1-xAsx solid solution compounds are isostructural with the binary helimagnets FeP and FeAs with MnP-type structure (sp. gr. Pnma) of the B31 family, their magnetic structure remained unclear. We studied two members of this family (x = 0.33 and 0.5) via microscopic site-selective techniques such as Mössbauer and NMR spectroscopy. Our results indicate that the helimagnetic nature of the ground state is preserved, but undergoes significant modifications. In particular, its ordering range seems to become drastically shorter, so that the local fields on the non-magnetic phosphorus atoms decrease several times compared to those in FeP, and even local fields on iron slightly decrease compared to FeP and FeAs. The ordering temperature for these fragmented structures is suppressed down to 20–30 K, which is significantly lower than the TN values for FeP and FeAs. Additionally, both compounds demonstrate higher sustainability to the external field than the parent compound FeP. | |
Hemmida, M.; Pakhira, S.; Johnston, D. C.; von Nidda, H. -A. Krug Observation of surface ferromagnons in the axion-insulating phase of the antiferromagnetic topological insulator EuSn2As2 Journal Article Phys. Rev. Research 8, 023309 (2026). @article{dp4g-dyll,
title = {Observation of surface ferromagnons in the axion-insulating phase of the antiferromagnetic topological insulator EuSn_{2}As_{2}},
author = {M. Hemmida and S. Pakhira and D. C. Johnston and H. -A. Krug von Nidda},
url = {https://link.aps.org/doi/10.1103/dp4g-dyll},
doi = {10.1103/dp4g-dyll},
year = {2026},
date = {2026-06-17},
urldate = {2026-06-01},
journal = {Phys. Rev. Research},
volume = {8},
number = {2},
pages = {023309},
abstract = {We report the study of spin dynamics of Eu2+ in the antiferromagnetic axion topological insulator EuSn2As2 by means of antiferromagnetic resonance at 9.34 GHz. Below the Néel temperature (T_N), two types of resonance modes, the conventional bulk antiferromagnetic resonance and additional surface ferromagnetic resonance, are observed. The latter turns out to be characteristic of the axion-insulating phase. Above T_N, we prove the existence of a Kosterlitz-Thouless scenario that is relevant for the spin relaxation in the Eu2+ layers. The absence of Korringa relaxation indicates the strong confinement of the conduction electrons at the Fermi level to the SnAs layers.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report the study of spin dynamics of Eu2+ in the antiferromagnetic axion topological insulator EuSn2As2 by means of antiferromagnetic resonance at 9.34 GHz. Below the Néel temperature (T_N), two types of resonance modes, the conventional bulk antiferromagnetic resonance and additional surface ferromagnetic resonance, are observed. The latter turns out to be characteristic of the axion-insulating phase. Above T_N, we prove the existence of a Kosterlitz-Thouless scenario that is relevant for the spin relaxation in the Eu2+ layers. The absence of Korringa relaxation indicates the strong confinement of the conduction electrons at the Fermi level to the SnAs layers. | |
Hirrle, M.; Röß-Ohlenroth, R.; Reschke, S.; Bredenkötter, B.; von Nidda, H. -A. Krug; Volkmer, D. Tuning of Jahn-Teller distortions via sterically enforced lattice enlargement of Cu(ta)2-type coordination polymers Journal Article J. Phys. Chem. Solids. 212, 113566 (2026). @article{hirrleTuningJahnTellerDistortions2026,
title = {Tuning of Jahn-Teller distortions via sterically enforced lattice enlargement of Cu(ta)_{2}-type coordination polymers},
author = {M. Hirrle and R. Röß-Ohlenroth and S. Reschke and B. Bredenkötter and H. -A. Krug von Nidda and D. Volkmer},
url = {https://www.sciencedirect.com/science/article/pii/S0022369726000521},
doi = {10.1016/j.jpcs.2026.113566},
year = {2026},
date = {2026-05-01},
urldate = {2026-05-01},
journal = {J. Phys. Chem. Solids.},
volume = {212},
pages = {113566},
abstract = {The control of Jahn-Teller distortions in copper-based coordination polymers is crucial for tuning their magnetic and structural properties. Here, we report the synthesis and characterization of two novel Cu(II)-based metal-organic frameworks (MOFs), Cu(mta)2 and Cu(cta)2, derived from modified triazole ligands. By introducing steric bulk through methyl and cyclopentyl substituents, we systematically investigate the effect of lattice enlargement on local coordination environments and magnetic behaviour. Single-crystal and powder X-ray diffraction analyses reveal that Cu(mta)2 exhibits static Jahn-Teller distortions similar to those observed in Cu(ta)2, whereas Cu(cta)2 crystallizes in an undistorted, near-ideal cubic structure. Magnetic susceptibility and electron spin resonance measurements show strong antiferromagnetic interactions and temperature-dependent g-factor anisotropy for Cu(ta)2 and Cu(mta)2, while Cu(cta)2 displays nearly isotropic magnetic behavior and only dynamically JT distortions without a cooperative phase transition. These results demonstrate that steric ligand design offers a powerful strategy to modulate the interplay between lattice structure and magnetic anisotropy. Our findings provide fundamental insights into the suppression of cooperative static Jahn-Teller distortions and open pathways for the targeted design of multifunctional MOFs with tailored structural and magnetic properties.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The control of Jahn-Teller distortions in copper-based coordination polymers is crucial for tuning their magnetic and structural properties. Here, we report the synthesis and characterization of two novel Cu(II)-based metal-organic frameworks (MOFs), Cu(mta)2 and Cu(cta)2, derived from modified triazole ligands. By introducing steric bulk through methyl and cyclopentyl substituents, we systematically investigate the effect of lattice enlargement on local coordination environments and magnetic behaviour. Single-crystal and powder X-ray diffraction analyses reveal that Cu(mta)2 exhibits static Jahn-Teller distortions similar to those observed in Cu(ta)2, whereas Cu(cta)2 crystallizes in an undistorted, near-ideal cubic structure. Magnetic susceptibility and electron spin resonance measurements show strong antiferromagnetic interactions and temperature-dependent g-factor anisotropy for Cu(ta)2 and Cu(mta)2, while Cu(cta)2 displays nearly isotropic magnetic behavior and only dynamically JT distortions without a cooperative phase transition. These results demonstrate that steric ligand design offers a powerful strategy to modulate the interplay between lattice structure and magnetic anisotropy. Our findings provide fundamental insights into the suppression of cooperative static Jahn-Teller distortions and open pathways for the targeted design of multifunctional MOFs with tailored structural and magnetic properties. | |
Nandi, S.; Das, R.; Hemmida, M.; Akbar, M. U.; von Nidda, H. -A. Krug; Sichelschmidt, J.; Mahapatra, S.; Schuller, M.; Büttgen, N.; Wilkinson, J.; Saravanan, M. P.; Dasgupta, I.; Mahajan, A. V. Novel Quantum Spin Liquid States in the S = 1/2 Three-Dimensional Compound Y3Cu2Sb3O14 Journal Article Phys. Rev. Lett. 136, 166502 (2026). @article{nandiNovelQuantumSpin2025,
title = {Novel Quantum Spin Liquid States in the S = 1/2 Three-Dimensional Compound Y_{3}Cu_{2}Sb_{3}O_{14}},
author = {S. Nandi and R. Das and M. Hemmida and M. U. Akbar and H. -A. Krug von Nidda and J. Sichelschmidt and S. Mahapatra and M. Schuller and N. Büttgen and J. Wilkinson and M. P. Saravanan and I. Dasgupta and A. V. Mahajan},
url = {https://doi.org/10.1103/2bps-xvl8},
doi = {10.1103/2bps-xvl8},
year = {2026},
date = {2026-04-22},
urldate = {2026-04-01},
journal = {Phys. Rev. Lett.},
volume = {136},
pages = {166502},
abstract = {The three-dimensional S=1/2 system Y3Cu2Sb3O14 consists of two inequivalent Cu2+ sites, each forming an edge shared triangular lattice. Our magnetic susceptibility 𝜒(𝑇), specific heat 𝐶𝑝(𝑇), 89Y nuclear magnetic resonance (NMR), muon spin relaxation (μSR), and electron spin resonance (ESR) measurements on this system confirm the absence of any long-range magnetic ordering and the persistence of spin dynamics down to 0.077 K. In 89Y NMR, we find an anomaly at about 120 K, which we suggest arises from a fraction of the spins condensing into a singlet (a valence bond solid, or VBS) state. A plateau in the muon relaxation rate is observed between 60 K and 10 K (signifying the VBS state from a fraction of the spins) followed by an increase and another plateau below about 1 K (presumably signifying the quantum spin liquid state from all the spins). Our density functional theory calculations find a dominant antiferromagnetic interaction along the body diagonal with inequivalent Cu(1) and Cu(2) ions alternately occupying the corners of the cube. All other near-neighbor interactions between the Cu ions are also found to be antiferromagnetic and are thought to drive the frustration.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The three-dimensional S=1/2 system Y3Cu2Sb3O14 consists of two inequivalent Cu2+ sites, each forming an edge shared triangular lattice. Our magnetic susceptibility 𝜒(𝑇), specific heat 𝐶𝑝(𝑇), 89Y nuclear magnetic resonance (NMR), muon spin relaxation (μSR), and electron spin resonance (ESR) measurements on this system confirm the absence of any long-range magnetic ordering and the persistence of spin dynamics down to 0.077 K. In 89Y NMR, we find an anomaly at about 120 K, which we suggest arises from a fraction of the spins condensing into a singlet (a valence bond solid, or VBS) state. A plateau in the muon relaxation rate is observed between 60 K and 10 K (signifying the VBS state from a fraction of the spins) followed by an increase and another plateau below about 1 K (presumably signifying the quantum spin liquid state from all the spins). Our density functional theory calculations find a dominant antiferromagnetic interaction along the body diagonal with inequivalent Cu(1) and Cu(2) ions alternately occupying the corners of the cube. All other near-neighbor interactions between the Cu ions are also found to be antiferromagnetic and are thought to drive the frustration. | |
2025
|
Grumbach, J.; Sourd, J.; Deeb, M.; Miyata, A.; Suwa, H.; Gottschall, T.; Hauspurg, A.; Chattopadhyay, S.; Rotter, M.; Granovsky, S.; Prodan, L.; Tsurkan, V.; Zherlitsyn, S.; Doerr, M.; Wosnitza, J. Contrasting magnetic behavior in MnSc2X4 (X = S, Se) spinel compounds investigated by magnetoelastic studies Journal Article Phys. Rev. B 112, 214415 (2025). @article{479d-4jvy,
title = {Contrasting magnetic behavior in MnSc_{2}X_{4} (X = S, Se) spinel compounds investigated by magnetoelastic studies},
author = {J. Grumbach and J. Sourd and M. Deeb and A. Miyata and H. Suwa and T. Gottschall and A. Hauspurg and S. Chattopadhyay and M. Rotter and S. Granovsky and L. Prodan and V. Tsurkan and S. Zherlitsyn and M. Doerr and J. Wosnitza},
url = {https://link.aps.org/doi/10.1103/479d-4jvy},
doi = {10.1103/479d-4jvy},
year = {2025},
date = {2025-12-08},
urldate = {2025-12-01},
journal = {Phys. Rev. B},
volume = {112},
number = {21},
pages = {214415},
abstract = {The spinel compounds MnSc2𝑋4 are highly frustrated and candidate materials for vortex-like 3 q magnetic states, such as skyrmions, with propagation vectors in the [111] plane. Because of the strong magnetoelastic coupling, we could extract a refined magnetic (𝐻,𝑇) phase diagram for MnSc2S4 from ultrasound and dilatometry measurements. We found a variety of magnetic phases, including the skyrmion phase, which is stable down to lowest temperatures. In comparison, we investigated MnSc2Se4, having a larger distance between the magnetic Mn3+ ions using the same methods. Unlike in MnSc2S4, we found no skyrmion phase and overall a lack of sharp anomalies indicative of phase transitions, neither in dilatometry nor ultrasound nor in specific heat and ac-susceptibility data. Motivated by our findings, we performed model calculations, which reproduced the experimentally observed magnetostriction and specific-heat results reasonably well.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The spinel compounds MnSc2𝑋4 are highly frustrated and candidate materials for vortex-like 3 q magnetic states, such as skyrmions, with propagation vectors in the [111] plane. Because of the strong magnetoelastic coupling, we could extract a refined magnetic (𝐻,𝑇) phase diagram for MnSc2S4 from ultrasound and dilatometry measurements. We found a variety of magnetic phases, including the skyrmion phase, which is stable down to lowest temperatures. In comparison, we investigated MnSc2Se4, having a larger distance between the magnetic Mn3+ ions using the same methods. Unlike in MnSc2S4, we found no skyrmion phase and overall a lack of sharp anomalies indicative of phase transitions, neither in dilatometry nor ultrasound nor in specific heat and ac-susceptibility data. Motivated by our findings, we performed model calculations, which reproduced the experimentally observed magnetostriction and specific-heat results reasonably well. | |
Nandi, S.; Jawale, M.; Bachhar, S.; Kumar, Rahul; Schuller, M.; Bag, R.; Wilkinson, J.; Sichelschmidt, J.; Sundaresan, A.; Haravifard, S.; Büttgen, N.; Mahajan, A. V. Observation of a gapped phase in the one-dimensional S = 1/2 Heisenberg antiferromagnetic chain Cu(Ampy)ClBr Journal Article Phys. Rev. B 112, 134437 (2025). @article{nandi_observationof_2025,
title = {Observation of a gapped phase in the one-dimensional S = 1/2 Heisenberg antiferromagnetic chain Cu(Ampy)ClBr},
author = {S. Nandi and M. Jawale and S. Bachhar and Rahul Kumar and M. Schuller and R. Bag and J. Wilkinson and J. Sichelschmidt and A. Sundaresan and S. Haravifard and N. Büttgen and A. V. Mahajan},
url = {https://link.aps.org/doi/10.1103/mkdv-8m61},
doi = {10.1103/mkdv-8m61},
year = {2025},
date = {2025-10-22},
urldate = {2025-10-22},
journal = {Phys. Rev. B},
volume = {112},
number = {13},
pages = {134437},
abstract = {Spin-1/2 Heisenberg antiferromagnetic frustrated spin-chain systems display exotic ground states with unconventional excitations and distinct quantum phase transitions as the ratio of next-nearest-neighbor to nearest-neighbor coupling is tuned. We present a comprehensive investigation of the structural, magnetic, and thermodynamics properties of the spin-1/2 compound, Cu(Ampy)ClBr(Ampy=C6H8N2=2 -(aminomethyl)pyridine) via x-ray diffraction, magnetization, specific heat, 1H nuclear magnetic resonance (NMR), electron spin resonance, and muon spin relaxation (𝜇SR) techniques. The crystal structure features an anisotropic triangular chain lattice of magnetic Cu2+ ions. Our bulk and local probe experiments detect neither long-range magnetic ordering nor spin freezing down to 0.06 K despite the presence of moderate antiferromagnetic interaction between Cu2+ spins as reflected by a Curie-Weiss temperature of about −9 K from the bulk susceptibility data. A broad maximum is observed at about 9 K in magnetic susceptibility and specific-heat data, indicating the onset of short-range spin correlations. At low temperatures, the zero-field magnetic specific heat and the 1H NMR spin-lattice relaxation rate follow an exponential temperature dependence, indicating the presence of gapped magnetic excitations. Furthermore, persistent spin dynamics down to 0.088 K observed by zero-field 𝜇SR evidences lack of any static magnetism.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Spin-1/2 Heisenberg antiferromagnetic frustrated spin-chain systems display exotic ground states with unconventional excitations and distinct quantum phase transitions as the ratio of next-nearest-neighbor to nearest-neighbor coupling is tuned. We present a comprehensive investigation of the structural, magnetic, and thermodynamics properties of the spin-1/2 compound, Cu(Ampy)ClBr(Ampy=C6H8N2=2 -(aminomethyl)pyridine) via x-ray diffraction, magnetization, specific heat, 1H nuclear magnetic resonance (NMR), electron spin resonance, and muon spin relaxation (𝜇SR) techniques. The crystal structure features an anisotropic triangular chain lattice of magnetic Cu2+ ions. Our bulk and local probe experiments detect neither long-range magnetic ordering nor spin freezing down to 0.06 K despite the presence of moderate antiferromagnetic interaction between Cu2+ spins as reflected by a Curie-Weiss temperature of about −9 K from the bulk susceptibility data. A broad maximum is observed at about 9 K in magnetic susceptibility and specific-heat data, indicating the onset of short-range spin correlations. At low temperatures, the zero-field magnetic specific heat and the 1H NMR spin-lattice relaxation rate follow an exponential temperature dependence, indicating the presence of gapped magnetic excitations. Furthermore, persistent spin dynamics down to 0.088 K observed by zero-field 𝜇SR evidences lack of any static magnetism. | |
Seidov, Z. Y.; Yatsyk, I. V.; Shestakov, A. V.; Ovchinnikov, A. S.; Vagizov, F. G.; Shustov, V. A.; Badelin, A. G.; Karpasyuk, V. K.; Najafzade, M. J.; Ibrahimov, I. N.; von Nidda, H. -A. Krug; Eremina, R. M. Griffiths phase and magnetocaloric effect in ferromagnetic La0.7Sr0.3Mn0.9Fe0.1−xZnxO3 (x = 0.05, 0.075 and 0.1) Journal Article J. Alloys Compd. 1040, 182887 (2025). @article{seidov_griffiths_2025,
title = {Griffiths phase and magnetocaloric effect in ferromagnetic La_{0.7}Sr_{0.3}Mn_{0.9}Fe_{0.1−x}Zn_{x}O_{3} (x = 0.05, 0.075 and 0.1)},
author = {Z. Y. Seidov and I. V. Yatsyk and A. V. Shestakov and A. S. Ovchinnikov and F. G. Vagizov and V. A. Shustov and A. G. Badelin and V. K. Karpasyuk and M. J. Najafzade and I. N. Ibrahimov and H. -A. Krug von Nidda and R. M. Eremina},
url = {https://www.sciencedirect.com/science/article/pii/S0925838825044482},
doi = {https://doi.org/10.1016/j.jallcom.2025.182887},
issn = {0925-8388},
year = {2025},
date = {2025-09-23},
urldate = {2025-09-01},
journal = {J. Alloys Compd.},
volume = {1040},
pages = {182887},
abstract = {The polycrystalline La0.7Sr0.3Mn0.9Fe0.1−xZnxO3 (x= 0.05, 0.075 and 0.1) have been investigated by means of electron spin resonance (ESR), magnetic susceptibility, magnetization, and Mössbauer measurements. Mössbauer studies for x = 0.05 indicate that Fe in these compounds is in the trivalent high-spin state. All compounds exhibits a paramagnetic to ferromagnetic transition at the Curie temperature TC. The Curie temperature TC decreases on increasing Zn content according to 278, 193 and 166 K for x = 0.05, 0.075 and 0.1, respectively. The existence of a Griffiths like phase is experimentally detected by means of magnetic susceptibility and ESR measurements and corroborated by theoretical modeling. We also observed a magnetocaloric effect with a maximum magnetic entropy change (textbarΔSMmaxtextbar) value occurring close to the Curie temperature TC, corresponding to textbarΔSMmaxtextbar = 2.9, 2.6 and 2.68 J/(kg K) under magnetic field change (ΔH) of 50 kOe for x = 0.05, 0.075 and 0.1, respectively. The relative cooling power values were found to vary between 0.25 and 0.31 kJ/kg.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The polycrystalline La0.7Sr0.3Mn0.9Fe0.1−xZnxO3 (x= 0.05, 0.075 and 0.1) have been investigated by means of electron spin resonance (ESR), magnetic susceptibility, magnetization, and Mössbauer measurements. Mössbauer studies for x = 0.05 indicate that Fe in these compounds is in the trivalent high-spin state. All compounds exhibits a paramagnetic to ferromagnetic transition at the Curie temperature TC. The Curie temperature TC decreases on increasing Zn content according to 278, 193 and 166 K for x = 0.05, 0.075 and 0.1, respectively. The existence of a Griffiths like phase is experimentally detected by means of magnetic susceptibility and ESR measurements and corroborated by theoretical modeling. We also observed a magnetocaloric effect with a maximum magnetic entropy change (textbarΔSMmaxtextbar) value occurring close to the Curie temperature TC, corresponding to textbarΔSMmaxtextbar = 2.9, 2.6 and 2.68 J/(kg K) under magnetic field change (ΔH) of 50 kOe for x = 0.05, 0.075 and 0.1, respectively. The relative cooling power values were found to vary between 0.25 and 0.31 kJ/kg. | |
Gotovko, S. K.; Ivanova, A. G.; Kudimkina, P. S.; Bush, A. A.; Kozlov, V. I.; Hemmida, M.; von Nidda, H. -A. Krug; Svistov, L. E. Low-frequency dynamics of LiCu3O3: An antiferromagnet on a strongly depleted square lattice Journal Article Phys. Rev. B 111, 064430 (2025). @article{gotovko_low-frequency_2025,
title = {Low-frequency dynamics of LiCu_{3}O_{3}: An antiferromagnet on a strongly depleted square lattice},
author = {S. K. Gotovko and A. G. Ivanova and P. S. Kudimkina and A. A. Bush and V. I. Kozlov and M. Hemmida and H. -A. Krug von Nidda and L. E. Svistov},
url = {https://link.aps.org/doi/10.1103/PhysRevB.111.064430},
doi = {10.1103/PhysRevB.111.064430},
year = {2025},
date = {2025-02-28},
urldate = {2025-02-01},
journal = {Phys. Rev. B},
volume = {111},
number = {6},
pages = {064430},
abstract = {We present the study of low-frequency dynamics of LiCu3O3 —an antiferromagnet on a strongly depleted square lattice. The crystal structure contains two types of square planes with different Li+ → Cu2+ substitution rates (20% and 40%). Recent nuclear magnetic resonance (NMR), magnetization measurements and neutron scattering experiments revealed the occurrence of antiferromagnetic order at Tc1=123K and the change of the magnetic state at Tc2≈30K. Electron spin resonance (ESR) intensity measurements confirmed that at Tc1=123K a magnetic phase transition of only a part of the sample occurs, while the rest of the sample remains paramagnetic. Supposedly, the order occurs in the magnetic planes with higher concentrations of magnetic ions. The ratio of ESR intensity values before and after the transition is in agreement with this suggestion. In the studied frequency and temperature range (18–140GHz, 30–300K) only one electron paramagnetic resonance (EPR) branch was observed. At temperatures T<30K, the ESR branch acquires a gap which gradually increases with temperature decrease. The behavior of the observed gap in the magnetic resonance spectra indicates that this gap is, in fact, a pseudogap of exchange nature associated with finite-sized clusters of magnetic ions.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We present the study of low-frequency dynamics of LiCu3O3 —an antiferromagnet on a strongly depleted square lattice. The crystal structure contains two types of square planes with different Li+ → Cu2+ substitution rates (20% and 40%). Recent nuclear magnetic resonance (NMR), magnetization measurements and neutron scattering experiments revealed the occurrence of antiferromagnetic order at Tc1=123K and the change of the magnetic state at Tc2≈30K. Electron spin resonance (ESR) intensity measurements confirmed that at Tc1=123K a magnetic phase transition of only a part of the sample occurs, while the rest of the sample remains paramagnetic. Supposedly, the order occurs in the magnetic planes with higher concentrations of magnetic ions. The ratio of ESR intensity values before and after the transition is in agreement with this suggestion. In the studied frequency and temperature range (18–140GHz, 30–300K) only one electron paramagnetic resonance (EPR) branch was observed. At temperatures T<30K, the ESR branch acquires a gap which gradually increases with temperature decrease. The behavior of the observed gap in the magnetic resonance spectra indicates that this gap is, in fact, a pseudogap of exchange nature associated with finite-sized clusters of magnetic ions. | |
Aqeel, A.; Kronseder, M.; Vlietstra, N.; Huebl, H.; Heuver, J. A.; Noheda, B.; Herrero-Martín, J.; Pellegrin, E.; Vasili, H. B.; Mostovoy, M.; Back, C. Spin Hall magnetoresistance and spin Seebeck effect in Pt textbarCoCr2O4 heterostructures Journal Article Sci. Technol. Adv. Mater. 26, 2457320 (2025). @article{aqeelSpinHallMagnetoresistance2025,
title = {Spin Hall magnetoresistance and spin Seebeck effect in Pt textbarCoCr_{2}O_{4} heterostructures},
author = {A. Aqeel and M. Kronseder and N. Vlietstra and H. Huebl and J. A. Heuver and B. Noheda and J. Herrero-Martín and E. Pellegrin and H. B. Vasili and M. Mostovoy and C. Back},
url = {https://doi.org/10.1080/14686996.2025.2457320},
doi = {10.1080/14686996.2025.2457320},
year = {2025},
date = {2025-02-12},
urldate = {2025-12-01},
journal = {Sci. Technol. Adv. Mater.},
volume = {26},
number = {1},
pages = {2457320},
abstract = {This study delves into spin current-induced phenomena, such as spin-Hall magnetoresistance and the spin Seebeck effect within Pt films deposited on a noncollinear magnet, CoCr 2O 4 (CCO), particularly at low temperatures. Detailed investigation of the angular dependencies of spin Hall magnetoresistance (SMR) and spin Seebeck effect (SSE) was carried out. The temperature-dependent behavior of both SMR and SSE signals exhibits a discernible variation correlated with different magnetic phases of CCO. To distinguish the contributions arising from magnetic proximity effects, we conducted X-ray magnetic dichroism (XMCD) at the Pt-M 3 edge. XMCD data from Pt/CCO heterostructures suggest that any magnetic moment associated with Pt, if present, is below the detection limit. This supports the notion that the observed signals primarily stem from SMR and SSE. This study offers insights into spin-current-driven phenomena, paving the way for potential spintronic applications. This study uniquely differentiates non-collinear magnetic phases in CoCr?O? using all-electrical SMR and SSE, validated by excluding proximity-induced magnetization via XMCD, advancing spintronic detection techniques.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
This study delves into spin current-induced phenomena, such as spin-Hall magnetoresistance and the spin Seebeck effect within Pt films deposited on a noncollinear magnet, CoCr 2O 4 (CCO), particularly at low temperatures. Detailed investigation of the angular dependencies of spin Hall magnetoresistance (SMR) and spin Seebeck effect (SSE) was carried out. The temperature-dependent behavior of both SMR and SSE signals exhibits a discernible variation correlated with different magnetic phases of CCO. To distinguish the contributions arising from magnetic proximity effects, we conducted X-ray magnetic dichroism (XMCD) at the Pt-M 3 edge. XMCD data from Pt/CCO heterostructures suggest that any magnetic moment associated with Pt, if present, is below the detection limit. This supports the notion that the observed signals primarily stem from SMR and SSE. This study offers insights into spin-current-driven phenomena, paving the way for potential spintronic applications. This study uniquely differentiates non-collinear magnetic phases in CoCr?O? using all-electrical SMR and SSE, validated by excluding proximity-induced magnetization via XMCD, advancing spintronic detection techniques. |  |
2024
|
Hemmida, M.; Masell, J.; Karube, K.; Ehlers, D.; von Nidda, H. -A. Krug; Tsurkan, V.; Tokura, Y.; Taguchi, Y.; Kézsmárki, I. Role of magnetic anisotropy in the antiskyrmion-host schreibersite magnets Journal Article Phys. Rev. B 110, 054416 (2024). @article{hemmida_role_2024,
title = {Role of magnetic anisotropy in the antiskyrmion-host schreibersite magnets},
author = {M. Hemmida and J. Masell and K. Karube and D. Ehlers and H. -A. Krug von Nidda and V. Tsurkan and Y. Tokura and Y. Taguchi and I. Kézsmárki},
doi = {10.1103/PhysRevB.110.054416},
year = {2024},
date = {2024-08-08},
urldate = {2024-08-08},
journal = {Phys. Rev. B},
volume = {110},
number = {5},
pages = {054416},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
|  |
Büttgen, N.; von Nidda, H. -A. Krug Magnetic resonance in quantum spin chains with competing exchange interactions Journal Article J. Phys. A: Math. Theor. 57, 313001 (2024). @article{buttgen_magnetic_2024,
title = {Magnetic resonance in quantum spin chains with competing exchange interactions},
author = {N. Büttgen and H. -A. Krug von Nidda},
doi = {10.1088/1751-8121/ad5e4c},
year = {2024},
date = {2024-07-18},
urldate = {2024-07-01},
journal = {J. Phys. A: Math. Theor.},
volume = {57},
number = {31},
pages = {313001},
abstract = {Based on a previous review on magnetic resonance in quantum spin chains (Krug von Nidda et al 2010 Eur. Phys. J. Spec. Top. 180 161–89) we report on further development in this field with special focus on transition–metal oxides and halogenides consisting of quasi one–dimensional spin systems, where both intra–and inter–chain exchange interaction may give rise to frustration effects and higher–order anisotropic exchange contributions like the Dzyaloshinskii–Moriya interaction become decisive for the formation of the magnetic ground state. Selected examples show how NMR and ESR contribute valuable information on the magnetic phases and exchange interactions involved: LiCuVO4 with competing nearest neighbour and next–nearest neighbour intra–chain exchange, LiCu2O2 with complex zig–zag chains, and Cs2CuCl4 where the chains form a triangular lattice with the inter–chain interaction weaker but of the same order of magnitude than the intra–chain interaction. The so called paper–chain compound Ba3Cu3In4O12, where each successive pair of CuO4 plaquettes is rotated by 90° with respect to its predecessor along the c–direction like in a paper–chain, provides an interesting topology of frustrated intra–chain exchange interactions. Finally, a few dimer systems are considered.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Based on a previous review on magnetic resonance in quantum spin chains (Krug von Nidda et al 2010 Eur. Phys. J. Spec. Top. 180 161–89) we report on further development in this field with special focus on transition–metal oxides and halogenides consisting of quasi one–dimensional spin systems, where both intra–and inter–chain exchange interaction may give rise to frustration effects and higher–order anisotropic exchange contributions like the Dzyaloshinskii–Moriya interaction become decisive for the formation of the magnetic ground state. Selected examples show how NMR and ESR contribute valuable information on the magnetic phases and exchange interactions involved: LiCuVO4 with competing nearest neighbour and next–nearest neighbour intra–chain exchange, LiCu2O2 with complex zig–zag chains, and Cs2CuCl4 where the chains form a triangular lattice with the inter–chain interaction weaker but of the same order of magnitude than the intra–chain interaction. The so called paper–chain compound Ba3Cu3In4O12, where each successive pair of CuO4 plaquettes is rotated by 90° with respect to its predecessor along the c–direction like in a paper–chain, provides an interesting topology of frustrated intra–chain exchange interactions. Finally, a few dimer systems are considered. | |
Hirschberger, M.; Szigeti, B. G.; Hemmida, M.; Hirschmann, M. M.; Esser, S.; Ohsumi, H.; Tanaka, Y.; Spitz, L.; Gao, S.; Kolincio, K. K.; Sagayama, H.; Nakao, H.; Yamasaki, Y.; Forró, L.; von Nidda, H. -A. Krug; Kézsmárki, I.; Arima, T.; Tokura, Y. Lattice-commensurate skyrmion texture in a centrosymmetric breathing kagome magnet Journal Article npj Quantum Mater. 9, 45 (2024). @article{hirschberger_lattice-commensurate_2024,
title = {Lattice-commensurate skyrmion texture in a centrosymmetric breathing kagome magnet},
author = {M. Hirschberger and B. G. Szigeti and M. Hemmida and M. M. Hirschmann and S. Esser and H. Ohsumi and Y. Tanaka and L. Spitz and S. Gao and K. K. Kolincio and H. Sagayama and H. Nakao and Y. Yamasaki and L. Forró and H. -A. Krug von Nidda and I. Kézsmárki and T. Arima and Y. Tokura},
doi = {10.1038/s41535-024-00654-2},
year = {2024},
date = {2024-05-23},
urldate = {2024-05-01},
journal = {npj Quantum Mater.},
volume = {9},
pages = {45},
abstract = {Skyrmion lattices (SkL) in centrosymmetric materials typically have a magnetic period on the nanometer-scale, so that the coupling between magnetic superstructures and the underlying crystal lattice cannot be neglected. We reveal the commensurate locking of a SkL to the atomic lattice in Gd3Ru4Al12 via high-resolution resonant elastic x-ray scattering (REXS). Weak easy-plane magnetic anisotropy, demonstrated here by a combination of ferromagnetic resonance and REXS, penalizes placing a skyrmion core on a site of the atomic lattice. Under these conditions, a commensurate SkL, locked to the crystal lattice, is stable at finite temperatures – but gives way to a competing incommensurate ground state upon cooling. We discuss the role of Umklapp-terms in the Hamiltonian for the formation of this lattice-locked state, its magnetic space group, and the role of slight discommensurations, or (line) defects in the magnetic texture. We also contrast our findings with the case of SkLs in noncentrosymmetric material platforms.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Skyrmion lattices (SkL) in centrosymmetric materials typically have a magnetic period on the nanometer-scale, so that the coupling between magnetic superstructures and the underlying crystal lattice cannot be neglected. We reveal the commensurate locking of a SkL to the atomic lattice in Gd3Ru4Al12 via high-resolution resonant elastic x-ray scattering (REXS). Weak easy-plane magnetic anisotropy, demonstrated here by a combination of ferromagnetic resonance and REXS, penalizes placing a skyrmion core on a site of the atomic lattice. Under these conditions, a commensurate SkL, locked to the crystal lattice, is stable at finite temperatures – but gives way to a competing incommensurate ground state upon cooling. We discuss the role of Umklapp-terms in the Hamiltonian for the formation of this lattice-locked state, its magnetic space group, and the role of slight discommensurations, or (line) defects in the magnetic texture. We also contrast our findings with the case of SkLs in noncentrosymmetric material platforms. | |
Daul, W. G.; Hirrle, M.; Eisfeld, B.; Kraft, M.; von Nidda, H. -A. Krug; Volkmer, D. Heteropentanuclear Ru(II)Cu(II)4 Kuratowski Complexes Assembled from a Ruthenium(II) Precursor Complex to Study Competing Exchange Interactions in M(II)(ta)2 Networks [ta(−) = 1,2,3-Triazolate] Journal Article Inorg. Chem. 63, 5027–5039 (2024), datadoi: 10.1021/acs.inorgchem.3c04478. @article{daulHeteropentanuclearRuIICuII4Kuratowski2024,
title = {Heteropentanuclear Ru(II)Cu(II)4 Kuratowski Complexes Assembled from a Ruthenium(II) Precursor Complex to Study Competing Exchange Interactions in M(II)(ta)2 Networks [ta(−) = 1,2,3-Triazolate]},
author = {W. G. Daul and M. Hirrle and B. Eisfeld and M. Kraft and H. -A. Krug von Nidda and D. Volkmer},
url = {https://doi.org/10.1021/acs.inorgchem.3c04478},
doi = {10.1021/acs.inorgchem.3c04478},
year = {2024},
date = {2024-03-05},
urldate = {2024-03-01},
journal = {Inorg. Chem.},
volume = {63},
number = {11},
pages = {5027–5039},
abstract = {We report a directed two-step synthesis toward pentanuclear Kuratowski complexes. First, six 5,6-dimethylbenzo[1,2,3]triazole ligands (Me2btaH) are coordinated to a single Ru(II) ion, providing a topologically ideal template for the addition of further metal ions. The synthesis and crystal structures of [RuCu4X4(Me2bta)6] [X = acetylacetonate (acac) and tris(3,5-dimethyl-1-pyrazolyl)borate (Tp*)] are described. Both represent new members of the family of so-called Kuratowski (K3,3) complexes. The coordination units feature triazolato-bridged metal-centered MM4 tetrahedra, which are known for frustrated magnetic interactions in both complexes and metal–organic frameworks. The novel Ru(II)-centered complexes were synthesized in order to investigate the influence of the presence or absence of a paramagnetic central metal ion in the Kuratowski complex. Superconducting quantum interference device and electron spin resonance measurements demonstrate that small deviations in bond lengths and valence angles can lead to the formation of pairs of magnetic exchange-coupled Cu(II) ions. Which Cu(II) ions pair up can be predicted in Jahn–Teller active compounds by the overlap of the respective orbitals. These data are compared with those gleaned for M(II)(ta)2 (ta = 1,2,3-triazolate) lattices, in which structurally similar MM4 tetrahedra constitute the secondary building units.},
note = {datadoi: 10.1021/acs.inorgchem.3c04478},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report a directed two-step synthesis toward pentanuclear Kuratowski complexes. First, six 5,6-dimethylbenzo[1,2,3]triazole ligands (Me2btaH) are coordinated to a single Ru(II) ion, providing a topologically ideal template for the addition of further metal ions. The synthesis and crystal structures of [RuCu4X4(Me2bta)6] [X = acetylacetonate (acac) and tris(3,5-dimethyl-1-pyrazolyl)borate (Tp*)] are described. Both represent new members of the family of so-called Kuratowski (K3,3) complexes. The coordination units feature triazolato-bridged metal-centered MM4 tetrahedra, which are known for frustrated magnetic interactions in both complexes and metal–organic frameworks. The novel Ru(II)-centered complexes were synthesized in order to investigate the influence of the presence or absence of a paramagnetic central metal ion in the Kuratowski complex. Superconducting quantum interference device and electron spin resonance measurements demonstrate that small deviations in bond lengths and valence angles can lead to the formation of pairs of magnetic exchange-coupled Cu(II) ions. Which Cu(II) ions pair up can be predicted in Jahn–Teller active compounds by the overlap of the respective orbitals. These data are compared with those gleaned for M(II)(ta)2 (ta = 1,2,3-triazolate) lattices, in which structurally similar MM4 tetrahedra constitute the secondary building units. | |
2023
|
Tóth, B.; Amelin, K.; Rõõm, T.; Nagel, U.; Bauernfeind, A.; Tsurkan, V.; Prodan, L.; von Nidda, H. -A. Krug; Scheffler, M.; Kézsmárki, I.; others, Broadband magnetic resonance spectroscopy in MnSc2S4 Journal Article Sci. Rep. 13, 11069 (2023). @article{toth_broadband_2023,
title = {Broadband magnetic resonance spectroscopy in MnSc_{2}S_{4}},
author = {B. Tóth and K. Amelin and T. Rõõm and U. Nagel and A. Bauernfeind and V. Tsurkan and L. Prodan and H. -A. Krug von Nidda and M. Scheffler and I. Kézsmárki and others},
doi = {10.1038/s41598-023-37911-6},
year = {2023},
date = {2023-01-01},
urldate = {2023-01-01},
journal = {Sci. Rep.},
volume = {13},
number = {1},
pages = {11069},
abstract = {Recent neutron scattering experiments suggested that frustrated magnetic interactions give rise to antiferromagnetic spiral and fractional skyrmion lattice phases in MnSc2S4. Here, to trace the signatures of these modulated phases, we studied the spin excitations of MnSc2S4 by THz spectroscopy at 300 mK and in magnetic fields up to 12 T and by broadband microwave spectroscopy at various temperatures up to 50 GHz. We found a single magnetic resonance with frequency linearly increasing in field. The small deviation of the Mn2+ ion g-factor from 2},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Recent neutron scattering experiments suggested that frustrated magnetic interactions give rise to antiferromagnetic spiral and fractional skyrmion lattice phases in MnSc2S4. Here, to trace the signatures of these modulated phases, we studied the spin excitations of MnSc2S4 by THz spectroscopy at 300 mK and in magnetic fields up to 12 T and by broadband microwave spectroscopy at various temperatures up to 50 GHz. We found a single magnetic resonance with frequency linearly increasing in field. The small deviation of the Mn2+ ion g-factor from 2 | |
