2026
|
Lao, H.; Kronseder, M.; Yuan, Z.; Narr, T.; Meier, T. N. G.; Mundigl, N.; Qu, X.; Wang, Z.; Back, C. H.; Chen, L. Alloying‐controlled tuning of interfacial spin‐orbit interaction and magnetic damping in crystalline FeCo thin films grown on GaAs(001) Journal Article Adv. Mater. (2026). @article{laoAlloyingcontrolledTuningInterfacial2026,
title = {Alloying‐controlled tuning of interfacial spin‐orbit interaction and magnetic damping in crystalline FeCo thin films grown on GaAs(001)},
author = {H. Lao and M. Kronseder and Z. Yuan and T. Narr and T. N. G. Meier and N. Mundigl and X. Qu and Z. Wang and C. H. Back and L. Chen},
url = {http://dx.doi.org/10.1002/adma.74841},
doi = {10.1002/adma.74841},
issn = {1521-4095},
year = {2026},
date = {2026-08-28},
urldate = {2026-08-01},
journal = {Adv. Mater.},
publisher = {Wiley},
abstract = {The discovery of intrinsic spin–orbit fields in non-centrosymmetric ferromagnets have attracted considerable interest for both fundamental studies and technological applications. However, once such materials are synthesized, the strength of the spin-orbit fields is difficult to tune because it is primarily a bulk property. Here, we demonstrate that the interfacial spin-orbit interaction (SOI) in single-crystalline Fe1−xCox thin films grown on GaAs(001) can be continuously tuned via alloying. Using spin-orbit ferromagnetic resonance, we find that the Landé g-factor, the Gilbert damping α, and the interfacial spin-orbit fields exhibit a common nonmonotonic dependence on Co concentration. A pronounced minimum occurs near x ≈ 0.2 where an ultra-low damping α ≈ 0.0015 is achieved. Furthermore, we observe linear scaling between α and (g − 2)2, suggesting that interfacial SOI may also contribute to magnetic relaxation. These results identify alloying as an effective knob to engineer interfacial SOI and damping in single crystalline ferromagnet/semiconductor heterostructures.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The discovery of intrinsic spin–orbit fields in non-centrosymmetric ferromagnets have attracted considerable interest for both fundamental studies and technological applications. However, once such materials are synthesized, the strength of the spin-orbit fields is difficult to tune because it is primarily a bulk property. Here, we demonstrate that the interfacial spin-orbit interaction (SOI) in single-crystalline Fe1−xCox thin films grown on GaAs(001) can be continuously tuned via alloying. Using spin-orbit ferromagnetic resonance, we find that the Landé g-factor, the Gilbert damping α, and the interfacial spin-orbit fields exhibit a common nonmonotonic dependence on Co concentration. A pronounced minimum occurs near x ≈ 0.2 where an ultra-low damping α ≈ 0.0015 is achieved. Furthermore, we observe linear scaling between α and (g − 2)2, suggesting that interfacial SOI may also contribute to magnetic relaxation. These results identify alloying as an effective knob to engineer interfacial SOI and damping in single crystalline ferromagnet/semiconductor heterostructures. |  |
Koraltan, S.; Sunny, J.; Karaman, T.; Peremadathil‐Pradeep, R.; Darwin, E.; Büttner, F.; Suess, D.; Hug, H. J.; Albrecht, M. Magnetic Force Microscopy Signatures of Higher‐Order Skyrmions and Antiskyrmions Journal Article Adv. Funct. Mater. 36, (2026). @article{koraltanMagneticForceMicroscopy2026,
title = {Magnetic Force Microscopy Signatures of Higher‐Order Skyrmions and Antiskyrmions},
author = {S. Koraltan and J. Sunny and T. Karaman and R. Peremadathil‐Pradeep and E. Darwin and F. Büttner and D. Suess and H. J. Hug and M. Albrecht},
url = {http://dx.doi.org/10.1002/adfm.202525716},
doi = {10.1002/adfm.202525716},
year = {2026},
date = {2026-03-13},
urldate = {2026-03-13},
journal = {Adv. Funct. Mater.},
volume = {36},
number = {41},
publisher = {Wiley},
abstract = {Higher-order skyrmions and antiskyrmions are topologically protected spin textures with integer topological charges beyond
±1, typically nucleating from vertical Bloch lines in domain walls. Until now, they have been reported only in ferromagnetic multilayers by Lorentz transmission electron microscopy (LTEM), which requires growth on ultrathin membranes and complicates their integration into spintronic devices. Moreover, LTEM often yields contrast patterns that are difficult to unambiguously assign to specific topological charges. Here, we demonstrate that magnetic force microscopy (MFM) operated under vacuum conditions provides a robust route to identify and distinguish higher-order spin textures in Co/Ni multilayers at room temperature. Supported by micromagnetic simulations, we show that MFM can resolve vertical Bloch lines as well as skyrmions and antiskyrmions with arbitrary charge. Our results establish advanced MFM as a powerful technique for the qualitative classification of complex spin textures, paving the way for their exploration and utilization in future skyrmionic device concepts.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Higher-order skyrmions and antiskyrmions are topologically protected spin textures with integer topological charges beyond
±1, typically nucleating from vertical Bloch lines in domain walls. Until now, they have been reported only in ferromagnetic multilayers by Lorentz transmission electron microscopy (LTEM), which requires growth on ultrathin membranes and complicates their integration into spintronic devices. Moreover, LTEM often yields contrast patterns that are difficult to unambiguously assign to specific topological charges. Here, we demonstrate that magnetic force microscopy (MFM) operated under vacuum conditions provides a robust route to identify and distinguish higher-order spin textures in Co/Ni multilayers at room temperature. Supported by micromagnetic simulations, we show that MFM can resolve vertical Bloch lines as well as skyrmions and antiskyrmions with arbitrary charge. Our results establish advanced MFM as a powerful technique for the qualitative classification of complex spin textures, paving the way for their exploration and utilization in future skyrmionic device concepts. |  |
Shao, J.; Kronseder, M.; Guo, J.; Mangold, M.; Pan, D.; Meier, T. N. G.; Zhao, W.; Zhao, J.; Back, C. H.; Chen, L. Electric-field tunable anisotropic g-Factor induced by spin pumping Journal Article Nano Letters 26, 2853–2860 (2026). @article{shaoElectricfieldTunableAnisotropic2026,
title = {Electric-field tunable anisotropic g-Factor induced by spin pumping},
author = {J. Shao and M. Kronseder and J. Guo and M. Mangold and D. Pan and T. N. G. Meier and W. Zhao and J. Zhao and C. H. Back and L. Chen},
url = {http://dx.doi.org/10.1021/acs.nanolett.5c05536},
doi = {10.1021/acs.nanolett.5c05536},
issn = {1530-6992},
year = {2026},
date = {2026-02-20},
urldate = {2026-02-01},
journal = {Nano Letters},
volume = {26},
number = {8},
pages = {2853–2860},
publisher = {American Chemical Society (ACS)},
abstract = {Spin pumping, a well-established phenomenon where the precessing magnetization of a ferromagnet (FM) injects a pure spin current into an adjacent nonmagnetic layer, is characteristically identified by the enhancement of magnetic damping in the FM. Theoretical work has also suggested that spin pumping can affect the Landé g-factoranother key parameter of ferromagnetic materials besides the magnetic damping. However, experimental evidence of this effect has remained limited. Here, we demonstrate that spin pumping can lead to significant modulation of the g-factor in a Py/AlOx/STO two-dimensional electron gas (2DEG) system with strong spin–orbit interaction. Specifically, we observe an anisotropic g-factor with 2-fold symmetry below the onset temperature of the 2DEG, and furthermore this anisotropy can be tuned when applying an external electric field. This work uncovers a previously overlooked effect and offers new possibilities for controlling magnetization dynamics in systems with a reduced dimension.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Spin pumping, a well-established phenomenon where the precessing magnetization of a ferromagnet (FM) injects a pure spin current into an adjacent nonmagnetic layer, is characteristically identified by the enhancement of magnetic damping in the FM. Theoretical work has also suggested that spin pumping can affect the Landé g-factoranother key parameter of ferromagnetic materials besides the magnetic damping. However, experimental evidence of this effect has remained limited. Here, we demonstrate that spin pumping can lead to significant modulation of the g-factor in a Py/AlOx/STO two-dimensional electron gas (2DEG) system with strong spin–orbit interaction. Specifically, we observe an anisotropic g-factor with 2-fold symmetry below the onset temperature of the 2DEG, and furthermore this anisotropy can be tuned when applying an external electric field. This work uncovers a previously overlooked effect and offers new possibilities for controlling magnetization dynamics in systems with a reduced dimension. | |
Guo, J.; Brizolla, G. M. S.; Rao, P.; Shao, J.; Huang, X. H.; Meier, T. N. G.; Xu, T.; Ji, P.; Finley, J.; Fabian, J.; Knolle, J.; Back, C.; Chen, L. Electric-current control of anomalous Hall effect Unpublished (2026), arXiv: 2601.03744. @unpublished{guoElectriccurrentControlAnomalous2026,
title = {Electric-current control of anomalous Hall effect},
author = {J. Guo and G. M. S. Brizolla and P. Rao and J. Shao and X. H. Huang and T. N. G. Meier and T. Xu and P. Ji and J. Finley and J. Fabian and J. Knolle and C. Back and L. Chen},
url = {https://arxiv.org/abs/2601.03744},
doi = {10.48550/arXiv.2601.03744},
year = {2026},
date = {2026-08-26},
urldate = {2026-08-01},
abstract = {We demonstrate robust and reversible electric-current control of the anomalous Hall effect (AHE) in a two-dimensional WTe2/Fe3GeTe2 (FGT) stack. Applying a current through Td-WTe2 leads to a giant modulation of the AHE of the adjacent FGT layer, with the relative change of the AHE conductivity exceeding 180},
note = {arXiv: 2601.03744},
keywords = {},
pubstate = {published},
tppubtype = {unpublished}
}
We demonstrate robust and reversible electric-current control of the anomalous Hall effect (AHE) in a two-dimensional WTe2/Fe3GeTe2 (FGT) stack. Applying a current through Td-WTe2 leads to a giant modulation of the AHE of the adjacent FGT layer, with the relative change of the AHE conductivity exceeding 180 |  |
Guo, J.; Rao, P.; Huang, X.; Xu, T.; Guo, Y.; Shao, J.; Sun, C.; Orekhov, A.; Meier, T. N. G.; Knolle, J.; Back, C. H.; Chen, L. Current-tunable room temperature ferromagnetism and current-driven phase transitions Unpublished (2026), arXiv:2603.27298. @unpublished{guoCurrenttunableRoomTemperature2026-03-282026,
title = {Current-tunable room temperature ferromagnetism and current-driven phase transitions},
author = {J. Guo and P. Rao and X. Huang and T. Xu and Y. Guo and J. Shao and C. Sun and A. Orekhov and T. N. G. Meier and J. Knolle and C. H. Back and L. Chen},
url = {https://arxiv.org/abs/2603.27298},
doi = {10.48550/arxiv2603.27298},
year = {2026},
date = {2026-03-28},
urldate = {2026-03-01},
publisher = {arXiv},
abstract = {It is generally assumed that the application of a charge-current in ferromagnetic metals suppresses their ferromagnetic order through trivial Joule heating. Here, we demonstrate that a charge current can instead enhance magnetic ordering. Using a WTe2/Fe3Ge2Te (FGT) stack as a model system, we show that a charge current flowing in WTe2 controls the ferromagnetic properties and magnetic phase transition of the adjacent FGT via a current-induced effective magnetic-field arising from orbital magnetization. Remarkably, the charge current drives a substantial enhancement of the Curie temperature, boosting it well above room temperature. Furthermore, we show that the charge-current enables controlled tuning of the phase transitions in FGT, which confirms the scaling behaviour of a ferromagnet-paramagnet phase transition. This work provides a pathway for integrating two-dimensional ferromagnets into spintronic functionalities at technologically relevant temperatures and for exploring novel current-driven phenomena in ferromagnetic systems.},
note = {arXiv:2603.27298},
keywords = {},
pubstate = {published},
tppubtype = {unpublished}
}
It is generally assumed that the application of a charge-current in ferromagnetic metals suppresses their ferromagnetic order through trivial Joule heating. Here, we demonstrate that a charge current can instead enhance magnetic ordering. Using a WTe2/Fe3Ge2Te (FGT) stack as a model system, we show that a charge current flowing in WTe2 controls the ferromagnetic properties and magnetic phase transition of the adjacent FGT via a current-induced effective magnetic-field arising from orbital magnetization. Remarkably, the charge current drives a substantial enhancement of the Curie temperature, boosting it well above room temperature. Furthermore, we show that the charge-current enables controlled tuning of the phase transitions in FGT, which confirms the scaling behaviour of a ferromagnet-paramagnet phase transition. This work provides a pathway for integrating two-dimensional ferromagnets into spintronic functionalities at technologically relevant temperatures and for exploring novel current-driven phenomena in ferromagnetic systems. | |
2025
|
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 |CoCr2O4 heterostructures Journal Article Sci. Technol. Adv. Mater. 26, 2457320 (2025). @article{aqeelSpinHallMagnetoresistance2025,
title = {Spin Hall magnetoresistance and spin Seebeck effect in Pt |CoCr_{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 = {2025-02-12},
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. | |
Tang, N.; Glamsch, S.; Aqeel, A.; Scheuchenpflug, L.; Schulze, M.; Liebald, C.; Rytz, D.; Guguschev, C.; Albrecht, M.; Gegenwart, P. Observation via spin Seebeck effect of macroscopic magnetic transport from emergent magnetic monopoles Unpublished (2025), arXiv:2509.18422. @unpublished{tang_observation_2025,
title = {Observation via spin Seebeck effect of macroscopic magnetic transport from emergent magnetic monopoles},
author = {N. Tang and S. Glamsch and A. Aqeel and L. Scheuchenpflug and M. Schulze and C. Liebald and D. Rytz and C. Guguschev and M. Albrecht and P. Gegenwart},
url = {https://arxiv.org/abs/2509.18422},
doi = {10.48550/arXiv.2509.18422},
year = {2025},
date = {2025-01-01},
urldate = {2025-09-22},
abstract = {Magnetic monopoles, elusive in high-energy physics, have been realised as emergent quasiparticles in solid-state systems, where their unique properties hold promise for novel spintronic applications. Magnetic monopoles have been invoked in diverse platforms, including skyrmion lattices, chiral magnets, soft ferromagnets, aritifical nanomagnets. Yet, a demonstration of their role in magnetic transport has remained elusive. Here, we report such an observation via the spin Seebeck effect in the bulk insulating pyrochlore oxide, spin ice Dy2Ti2O7. By applying a thermal gradient perpendicular to a [111]-oriented magnetic field, we detect a transverse spin Seebeck voltage marked by a dominant peak at the onset of monopole proliferation, accompanied by a secondary feature and frequency-dependent behavior. Our findings establish a direct link between monopole dynamics and magnetic transport in an insulating medium, establishing a new pathway for probing fractionalized excitations and advancing towards novel spintronic applications.},
note = {arXiv:2509.18422},
keywords = {},
pubstate = {published},
tppubtype = {unpublished}
}
Magnetic monopoles, elusive in high-energy physics, have been realised as emergent quasiparticles in solid-state systems, where their unique properties hold promise for novel spintronic applications. Magnetic monopoles have been invoked in diverse platforms, including skyrmion lattices, chiral magnets, soft ferromagnets, aritifical nanomagnets. Yet, a demonstration of their role in magnetic transport has remained elusive. Here, we report such an observation via the spin Seebeck effect in the bulk insulating pyrochlore oxide, spin ice Dy2Ti2O7. By applying a thermal gradient perpendicular to a [111]-oriented magnetic field, we detect a transverse spin Seebeck voltage marked by a dominant peak at the onset of monopole proliferation, accompanied by a secondary feature and frequency-dependent behavior. Our findings establish a direct link between monopole dynamics and magnetic transport in an insulating medium, establishing a new pathway for probing fractionalized excitations and advancing towards novel spintronic applications. |  |
2024
|
Chen, L.; Sun, Y.; Mankovsky, S.; Meier, T. N. G.; Kronseder, M.; Sun, C.; Orekhov, A.; Ebert, H.; Weiss, D.; Back, C. H. Signatures of magnetism control by flow of angular momentum Journal Article Nature 633, 548–553 (2024), datadoi: 10.17605/OSF.IO/RZMUJ. @article{chenSignaturesMagnetismControl2024,
title = {Signatures of magnetism control by flow of angular momentum},
author = {L. Chen and Y. Sun and S. Mankovsky and T. N. G. Meier and M. Kronseder and C. Sun and A. Orekhov and H. Ebert and D. Weiss and C. H. Back},
doi = {10.1038/s41586-024-07914-y},
issn = {1476-4687},
year = {2024},
date = {2024-09-04},
urldate = {2024-09-01},
journal = {Nature},
volume = {633},
number = {8030},
pages = {548–553},
abstract = {Exploring new strategies to manipulate the order parameter of magnetic materials by electrical means is of great importance not only for advancing our understanding of fundamental magnetism but also for unlocking potential applications. A well-established concept uses gate voltages to control magnetic properties by modulating the carrier population in a capacitor structure1–5. Here we show that, in Pt/Al/Fe/GaAs(001) multilayers, the application of an in-plane charge current in Pt leads to a shift in the ferromagnetic resonance field depending on the microwave frequency when the Fe film is sufficiently thin. The experimental observation is interpreted as a current-induced modification of the magnetocrystalline anisotropy ΔHA of Fe. We show that (1) ΔHA decreases with increasing Fe film thickness and is connected to the damping-like torque; and (2) ΔHA depends not only on the polarity of charge current but also on the magnetization direction, that is, ΔHA has an opposite sign when the magnetization direction is reversed. The symmetry of the modification is consistent with a current-induced spin6–8 and/or orbit9–13 accumulation, which, respectively, act on the spin and/or orbit component of the magnetization. In this study, as Pt is regarded as a typical spin current source6,14, the spin current can play a dominant part. The control of magnetism by a spin current results from the modified exchange splitting of the majority and minority spin bands, providing functionality that was previously unknown and could be useful in advanced spintronic devices.},
note = {datadoi: 10.17605/OSF.IO/RZMUJ},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Exploring new strategies to manipulate the order parameter of magnetic materials by electrical means is of great importance not only for advancing our understanding of fundamental magnetism but also for unlocking potential applications. A well-established concept uses gate voltages to control magnetic properties by modulating the carrier population in a capacitor structure1–5. Here we show that, in Pt/Al/Fe/GaAs(001) multilayers, the application of an in-plane charge current in Pt leads to a shift in the ferromagnetic resonance field depending on the microwave frequency when the Fe film is sufficiently thin. The experimental observation is interpreted as a current-induced modification of the magnetocrystalline anisotropy ΔHA of Fe. We show that (1) ΔHA decreases with increasing Fe film thickness and is connected to the damping-like torque; and (2) ΔHA depends not only on the polarity of charge current but also on the magnetization direction, that is, ΔHA has an opposite sign when the magnetization direction is reversed. The symmetry of the modification is consistent with a current-induced spin6–8 and/or orbit9–13 accumulation, which, respectively, act on the spin and/or orbit component of the magnetization. In this study, as Pt is regarded as a typical spin current source6,14, the spin current can play a dominant part. The control of magnetism by a spin current results from the modified exchange splitting of the majority and minority spin bands, providing functionality that was previously unknown and could be useful in advanced spintronic devices. | |
