Energy and momentum relaxation through the Curie temperature in an itinerant ferromagnet

Fuente: arXiv
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Main Authors: Bhandia, Rishi, Priessnitz, Tim, Liang, Jiahao, Rabinovich, Ksenia S., Romero III, Ralph, Katsumi, Kota, Tran, Thi Thu Huong, Christiani, Georg, Logvenov, Gennady, Keimer, Bernhard, Armitage, N. P.
Format: Preprint
Published: 2024
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author Bhandia, Rishi
Priessnitz, Tim
Liang, Jiahao
Rabinovich, Ksenia S.
Romero III, Ralph
Katsumi, Kota
Tran, Thi Thu Huong
Christiani, Georg
Logvenov, Gennady
Keimer, Bernhard
Armitage, N. P.
author_facet Bhandia, Rishi
Priessnitz, Tim
Liang, Jiahao
Rabinovich, Ksenia S.
Romero III, Ralph
Katsumi, Kota
Tran, Thi Thu Huong
Christiani, Georg
Logvenov, Gennady
Keimer, Bernhard
Armitage, N. P.
contents In this work, we combine conventional linear response time-domain THz spectroscopy with non-linear THz-pump THz-probe techniques to study metallic strained thin films of $\mathrm{Ca}_2\mathrm{RuO}_4$, which undergo a transition into a ferromagnetic state at 10 K. Such measurements allowing us to independently measure momentum and energy relaxation rates. We find that while the momentum relaxation rate decreases significantly at the ferromagnetic transition, the energy relaxation rate remains unaffected by the emergence of magnetic order. This shows that the dominant changes to scattering across the transition correspond to scatterings that relax momentum without relaxing energy. It is consistent with a scenario where energy is not carried off by coupling to collective magnetic degrees of freedom. Instead, the principal channel for energy relaxation remains the conventional one e.g. coupling to acoustic phonons. This observation validates the approximation used in the conventional understanding of resistive anomalies of ferromagnets across the Curie temperature, which due to critical slowing down, spin fluctuations can be treated as effectively static and scattering off of them elastic. This scenario can likely be extended to resistive anomalies at other phase transitions to charge- and spin-density wave states in kagome metals or pnictide system
format Preprint
id arxiv_https___arxiv_org_abs_2412_08749
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Energy and momentum relaxation through the Curie temperature in an itinerant ferromagnet
Bhandia, Rishi
Priessnitz, Tim
Liang, Jiahao
Rabinovich, Ksenia S.
Romero III, Ralph
Katsumi, Kota
Tran, Thi Thu Huong
Christiani, Georg
Logvenov, Gennady
Keimer, Bernhard
Armitage, N. P.
Strongly Correlated Electrons
Materials Science
In this work, we combine conventional linear response time-domain THz spectroscopy with non-linear THz-pump THz-probe techniques to study metallic strained thin films of $\mathrm{Ca}_2\mathrm{RuO}_4$, which undergo a transition into a ferromagnetic state at 10 K. Such measurements allowing us to independently measure momentum and energy relaxation rates. We find that while the momentum relaxation rate decreases significantly at the ferromagnetic transition, the energy relaxation rate remains unaffected by the emergence of magnetic order. This shows that the dominant changes to scattering across the transition correspond to scatterings that relax momentum without relaxing energy. It is consistent with a scenario where energy is not carried off by coupling to collective magnetic degrees of freedom. Instead, the principal channel for energy relaxation remains the conventional one e.g. coupling to acoustic phonons. This observation validates the approximation used in the conventional understanding of resistive anomalies of ferromagnets across the Curie temperature, which due to critical slowing down, spin fluctuations can be treated as effectively static and scattering off of them elastic. This scenario can likely be extended to resistive anomalies at other phase transitions to charge- and spin-density wave states in kagome metals or pnictide system
title Energy and momentum relaxation through the Curie temperature in an itinerant ferromagnet
topic Strongly Correlated Electrons
Materials Science
url https://arxiv.org/abs/2412.08749