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arXiv · 2303.15722

Giant magnetocaloric effect in magnets down to the monolayer limit

Weiwei He·Yan Yin·Qihua Gong·Richard F. L. Evans·Oliver Gutfleisch·Baixiang Xu·Min Yi·Wanlin Guo
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Abstract

Two-dimensional magnets could potentially revolutionize information technology, but their potential application to cooling technology and magnetocaloric effect (MCE) in a material down to the monolayer limit remain unexplored. Herein, we reveal through multiscale calculations the existence of giant MCE and its strain tunability in monolayer magnets such as CrX$_3$ (X=F, Cl, Br, I), CrAX (A=O, S, Se; X=F, Cl, Br, I), and Fe$_3$GeTe$_2$. The maximum adiabatic temperature change ($\Delta T_\text{ad}^\text{max}$), maximum isothermal magnetic entropy change, and specific cooling power in monolayer CrF$_3$ are found as high as 11 K, 35 $\mu$Jm$^{-2}$K$^{-1}$, and 3.5 nWcm$^{-2}$ under a magnetic field of 5 T, respectively. A 2% biaxial and 5% $a$-axis uniaxial compressive strain can remarkably increase $\Delta T_\text{ad}^\text{max}$ of CrCl$_3$ and CrOF by 230% and 37% (up to 15.3 and 6.0 K), respectively. It is found that large net magnetic moment per unit area favors improved MCE. These findings advocate the giant-MCE monolayer magnets, opening new opportunities for magnetic cooling at nanoscale.

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Weiwei He, Yan Yin, Qihua Gong, Richard F. L. Evans, Oliver Gutfleisch, Baixiang Xu, Min Yi, Wanlin Guo. 2023-03-28. Giant magnetocaloric effect in magnets down to the monolayer limit. https://arxiv.org/abs/2303.15722

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