Sensor free, self regulating thermal switching via anomalous Ettingshausen effect and spin reorientation in DyCo5

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Main Authors: Wang, Shibo, Tsuchiura, Hiroki, Terakado, Nobuaki
Format: Preprint
Published: 2025
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author Wang, Shibo
Tsuchiura, Hiroki
Terakado, Nobuaki
author_facet Wang, Shibo
Tsuchiura, Hiroki
Terakado, Nobuaki
contents We propose a sensor free, self regulating thermal switch that combines the anomalous Ettingshausen effect (AEE) with a temperature driven spin reorientation transition (SRT) in the rare earth cobalt compound DyCo$_5$. Using density functional theory and the Kubo linear-response formalism, we compute the anomalous Hall conductivity $σ_{xy}(\varepsilon)$ and the finite temperature anomalous Nernst conductivity $α_{xy}(T)$ for two magnetization directions, magnetization parallel and perpendicular to the crystallographic c axis. While the intrinsic $σ_{xy}$ at the Fermi level remains sizable for both orientations, $α_{xy}$ exhibits an about two orders of magnitude contrast in the SRT temperature window. This contrast is consistent with the low temperature Mott relation through the energy slope $\partial_\varepsilon σ_{xy}(\varepsilon)\rvert_{E_{\mathrm F}}$ and is traced to strongly peaked Berry curvature hot spots generated by spin orbit coupling induced avoided crossings of Co $3d$ bands. Combining $α_{xy}$ with longitudinal transport coefficients, we estimate device level metrics, namely the anomalous Nernst thermopower $S_{\mathrm{ANE}}$ and the Ettingshausen coefficient $Π_{\mathrm{AEE}}=T S_{\mathrm{ANE}}$, and demonstrate robust orientation controlled switching under a fixed in plane bias current. These results establish a materials based route to compact thermal control without external sensors or feedback electronics and provide a concrete example that the proposed principle can be realized in an existing ferromagnet.
format Preprint
id arxiv_https___arxiv_org_abs_2512_14335
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Sensor free, self regulating thermal switching via anomalous Ettingshausen effect and spin reorientation in DyCo5
Wang, Shibo
Tsuchiura, Hiroki
Terakado, Nobuaki
Applied Physics
Materials Science
We propose a sensor free, self regulating thermal switch that combines the anomalous Ettingshausen effect (AEE) with a temperature driven spin reorientation transition (SRT) in the rare earth cobalt compound DyCo$_5$. Using density functional theory and the Kubo linear-response formalism, we compute the anomalous Hall conductivity $σ_{xy}(\varepsilon)$ and the finite temperature anomalous Nernst conductivity $α_{xy}(T)$ for two magnetization directions, magnetization parallel and perpendicular to the crystallographic c axis. While the intrinsic $σ_{xy}$ at the Fermi level remains sizable for both orientations, $α_{xy}$ exhibits an about two orders of magnitude contrast in the SRT temperature window. This contrast is consistent with the low temperature Mott relation through the energy slope $\partial_\varepsilon σ_{xy}(\varepsilon)\rvert_{E_{\mathrm F}}$ and is traced to strongly peaked Berry curvature hot spots generated by spin orbit coupling induced avoided crossings of Co $3d$ bands. Combining $α_{xy}$ with longitudinal transport coefficients, we estimate device level metrics, namely the anomalous Nernst thermopower $S_{\mathrm{ANE}}$ and the Ettingshausen coefficient $Π_{\mathrm{AEE}}=T S_{\mathrm{ANE}}$, and demonstrate robust orientation controlled switching under a fixed in plane bias current. These results establish a materials based route to compact thermal control without external sensors or feedback electronics and provide a concrete example that the proposed principle can be realized in an existing ferromagnet.
title Sensor free, self regulating thermal switching via anomalous Ettingshausen effect and spin reorientation in DyCo5
topic Applied Physics
Materials Science
url https://arxiv.org/abs/2512.14335