Meier, T. N. G.; Back, C. Thermal stability of skyrmions Journal Article J. Phys.: Condens. Matter 38, 423004 (2026), datadoi: 10.14459/2026mp1859939. @article{meierThermalStabilitySkyrmions2026,
title = {Thermal stability of skyrmions},
author = {T. N. G. Meier and C. Back},
url = {http://dx.doi.org/10.1088/1361-648X/aeb085},
doi = {10.1088/1361-648x/aeb085},
issn = {1361-648X},
year = {2026},
date = {2026-10-23},
urldate = {2026-10-01},
journal = {J. Phys.: Condens. Matter},
volume = {38},
number = {42},
pages = {423004},
publisher = {IOP Publishing},
abstract = {Magnetic skyrmions are vortex-like magnetic textures with a topologically nontrivial spin structure making a continuous transformation from the skyrmion to the uniform state impossible. Hence skyrmions are regarded as topologically protected attracting large interest concerning applications in data storage, neuromorphic computing, and digital logic. For such kind of applications an extraordinary stability of the skyrmion state against thermal fluctuations is required. In real matter, due to its discrete nature, topological protection translates into the existence of an energy barrier between the skyrmion and the uniform state leading to a finite skyrmion lifetime. Therefore the experimental determination of the skyrmion lifetime becomes important. Within this work we focus on experimental studies of the skyrmion lifetime in a variety of magnetic systems ranging from monolayers to bulk samples. We discuss previous experimental studies on the thermal stability of magnetic skyrmions in systems based on Fe/Ir(111) and in B20-materials. New experimental results on skyrmion nucleation and decay are obtained for thin Ni/Fe-films on Cu(001) using threshold photoemission magnetic circular dichroism in combination with photoemission electron microscopy (TP-MCD-PEEM). The results are interpreted using an Arrhenius-like activation behavior and evaluated regarding energy barriers and pre-exponential factors of the skyrmion dynamics.},
note = {datadoi: 10.14459/2026mp1859939},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Magnetic skyrmions are vortex-like magnetic textures with a topologically nontrivial spin structure making a continuous transformation from the skyrmion to the uniform state impossible. Hence skyrmions are regarded as topologically protected attracting large interest concerning applications in data storage, neuromorphic computing, and digital logic. For such kind of applications an extraordinary stability of the skyrmion state against thermal fluctuations is required. In real matter, due to its discrete nature, topological protection translates into the existence of an energy barrier between the skyrmion and the uniform state leading to a finite skyrmion lifetime. Therefore the experimental determination of the skyrmion lifetime becomes important. Within this work we focus on experimental studies of the skyrmion lifetime in a variety of magnetic systems ranging from monolayers to bulk samples. We discuss previous experimental studies on the thermal stability of magnetic skyrmions in systems based on Fe/Ir(111) and in B20-materials. New experimental results on skyrmion nucleation and decay are obtained for thin Ni/Fe-films on Cu(001) using threshold photoemission magnetic circular dichroism in combination with photoemission electron microscopy (TP-MCD-PEEM). The results are interpreted using an Arrhenius-like activation behavior and evaluated regarding energy barriers and pre-exponential factors of the skyrmion dynamics. |
Ranaut, D.; Unnikrishnan, G.; M, Samraj; Channarayappa, S. K.; Mukharjee, P. K.; Saravanan, P.; Gegenwart, P.; Jaiswal-Nagar, D. Frustrated Garnet Gd3Te2Li3O12 for High-Performance Sub-Kelvin Adiabatic Demagnetization Refrigeration Journal Article ACS Appl. Electron. Mater. (2026). @article{ranautFrustratedGarnetGd3Te2Li3O122026,
title = {Frustrated Garnet Gd_{3}Te_{2}Li_{3}O_{12} for High-Performance Sub-Kelvin Adiabatic Demagnetization Refrigeration},
author = {D. Ranaut and G. Unnikrishnan and Samraj M and S. K. Channarayappa and P. K. Mukharjee and P. Saravanan and P. Gegenwart and D. Jaiswal-Nagar},
url = {https://doi.org/10.1021/acsaelm.6c01619},
doi = {10.1021/acsaelm.6c01619},
issn = {2637-6113},
year = {2026},
date = {2026-10-22},
urldate = {2026-10-01},
journal = {ACS Appl. Electron. Mater.},
abstract = {Owing to the limited availability and high cost of 3He, adiabatic demagnetization refrigeration (ADR) has gained considerable attention as an efficient technology for ultralow-temperature applications. Here, we demonstrate the frustrated garnet Gd3Te2Li3O12 (GTLG) as a high-performance ADR material with substantially improved cooling capability over the commercial benchmark Gd3Ga5O12 (GGG). Direct ADR measurements reveal a minimum temperature of 165 mK for GTLG, nearly two-fold lower than that of GGG (320 mK). Under a cryostat bath temperature of 1.8 K, GTLG maintains temperatures below 1 K for more than 12 h and below the 3He-temperature (0.4 K) for over 3 h, demonstrating excellent temperature stability for prolonged cryogenic operation. Magnetic and thermodynamic measurements show that GTLG undergoes antiferromagnetic ordering at TN ∼ 0.25 K while retaining strong magnetic frustration and a large magnetic entropy reservoir favorable for efficient demagnetization cooling. Field-dependent heat capacity and magnetic Grüneisen parameter measurements further reveal the presence of field-induced critical behavior that enables cooling below TN through enhanced entropy accumulation near the critical region. These findings establish GTLG as a promising next-generation magnetic refrigerant and highlight field-induced criticality as an effective design principle for developing advanced materials for ultralow-temperature refrigeration.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Owing to the limited availability and high cost of 3He, adiabatic demagnetization refrigeration (ADR) has gained considerable attention as an efficient technology for ultralow-temperature applications. Here, we demonstrate the frustrated garnet Gd3Te2Li3O12 (GTLG) as a high-performance ADR material with substantially improved cooling capability over the commercial benchmark Gd3Ga5O12 (GGG). Direct ADR measurements reveal a minimum temperature of 165 mK for GTLG, nearly two-fold lower than that of GGG (320 mK). Under a cryostat bath temperature of 1.8 K, GTLG maintains temperatures below 1 K for more than 12 h and below the 3He-temperature (0.4 K) for over 3 h, demonstrating excellent temperature stability for prolonged cryogenic operation. Magnetic and thermodynamic measurements show that GTLG undergoes antiferromagnetic ordering at TN ∼ 0.25 K while retaining strong magnetic frustration and a large magnetic entropy reservoir favorable for efficient demagnetization cooling. Field-dependent heat capacity and magnetic Grüneisen parameter measurements further reveal the presence of field-induced critical behavior that enables cooling below TN through enhanced entropy accumulation near the critical region. These findings establish GTLG as a promising next-generation magnetic refrigerant and highlight field-induced criticality as an effective design principle for developing advanced materials for ultralow-temperature refrigeration. |
Pazmino, E. I.; Feng, S.; Dhakal, R.; Rousochatzakis, I.; Winter, S. M.; Knolle, J.; Tsirlin, A. A. Beyond Kitaev exchange: Γ'-driven magnetism in Ag3LiRh2O6 Unpublished (2026), arXiv:2610.19770. @unpublished{pazminoKitaevExchangeGammadriven2026,
title = {Beyond Kitaev exchange: Γ'-driven magnetism in Ag_{3}LiRh_{2}O_{6}},
author = {E. I. Pazmino and S. Feng and R. Dhakal and I. Rousochatzakis and S. M. Winter and J. Knolle and A. A. Tsirlin},
url = {https://arxiv.org/abs/2610.19770},
doi = {10.48550/arXiv.2610.19770},
year = {2026},
date = {2026-10-14},
urldate = {2026-10-14},
abstract = {In Kitaev magnets, frustration arises from bond-dependent spin anisotropic interactions, which can potentially realize sought-after quantum spin liquid phases. However, material realizations with dominating Kitaev exchange are scarce and the broad parameter space of extended Kitaev models remains largely unexplored experimentally. Here, we use density-functional theory, cluster many-body, spin-wave, and density-matrix renormalization calculations to show that the recently discovered honeycomb rhodate Ag3LiRh2O6 hosts an off-diagonal exchange Γ′1 that is second in magnitude only to the ferromagnetic Kitaev exchange K1. This combination of K1 and Γ′1 explains key experimental observations, an unusually high magnetic ordering temperature of 94 K at ambient pressure and its rapid decrease under hydrostatic pressure as Ag3LiRh2O6 evolves from ferromagnetic toward zigzag order within the honeycomb planes. Our spin-wave calculations further predict an unusual topology of the magnon bands arising from the Γ′1 term in the spin Hamiltonian of the honeycomb layer. We show that the large trigonal splitting of t2g states enhances Γ′1, the hitherto underappreciated term in Kitaev magnets, and opens the way to new interesting regimes of the extended Kitaev model.},
note = {arXiv:2610.19770},
keywords = {},
pubstate = {published},
tppubtype = {unpublished}
}
In Kitaev magnets, frustration arises from bond-dependent spin anisotropic interactions, which can potentially realize sought-after quantum spin liquid phases. However, material realizations with dominating Kitaev exchange are scarce and the broad parameter space of extended Kitaev models remains largely unexplored experimentally. Here, we use density-functional theory, cluster many-body, spin-wave, and density-matrix renormalization calculations to show that the recently discovered honeycomb rhodate Ag3LiRh2O6 hosts an off-diagonal exchange Γ′1 that is second in magnitude only to the ferromagnetic Kitaev exchange K1. This combination of K1 and Γ′1 explains key experimental observations, an unusually high magnetic ordering temperature of 94 K at ambient pressure and its rapid decrease under hydrostatic pressure as Ag3LiRh2O6 evolves from ferromagnetic toward zigzag order within the honeycomb planes. Our spin-wave calculations further predict an unusual topology of the magnon bands arising from the Γ′1 term in the spin Hamiltonian of the honeycomb layer. We show that the large trigonal splitting of t2g states enhances Γ′1, the hitherto underappreciated term in Kitaev magnets, and opens the way to new interesting regimes of the extended Kitaev model. |
