Enhanced Neel temperature and unusual thermal expansion in flux-grown FeCrAs crystals

Fuente: arXiv
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Main Authors: McGuire, Michael A., Cook, Matthew S., Ortiz, Brenden R., Yan, Jiaqiang, May, Andrew F.
Format: Preprint
Published: 2025
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author McGuire, Michael A.
Cook, Matthew S.
Ortiz, Brenden R.
Yan, Jiaqiang
May, Andrew F.
author_facet McGuire, Michael A.
Cook, Matthew S.
Ortiz, Brenden R.
Yan, Jiaqiang
May, Andrew F.
contents We report results from our experimental investigation of the distorted-kagome compound FeCrAs. For this work, we developed a procedure using tin metal as a flux to produce needlelike crystals. The crystals were characterized by single crystal x-ray diffraction as well as measurements of magnetization, electrical transport, and heat capacity. The physical behaviors are generally similar to published results on crystals grown from a stoichiometric melt with two notable exceptions. The Sommerfeld coefficient is found to be 18 mJ/K2/mol, a little more than half of the previously reported value, and the Neel temperature is found to be 150 K, about 25K higher than in previous reports. The reason for these discrepancies are uncertain, but they may be related to differences in stoichiometry or disorder; it is expected that the Cr/Fe ratio has some variability in this compound. In addition, we find unusual thermal expansion behavior, with an anomaly at the Neel temperature and nearly temperature independent thermal expansion along the hexagonal c-axis above this transition. This suggests significant spin-lattice coupling, which may provide insight into non-metallic transport properties that have been associated with anomalous charge carrier scattering.
format Preprint
id arxiv_https___arxiv_org_abs_2505_21735
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Enhanced Neel temperature and unusual thermal expansion in flux-grown FeCrAs crystals
McGuire, Michael A.
Cook, Matthew S.
Ortiz, Brenden R.
Yan, Jiaqiang
May, Andrew F.
Materials Science
Strongly Correlated Electrons
We report results from our experimental investigation of the distorted-kagome compound FeCrAs. For this work, we developed a procedure using tin metal as a flux to produce needlelike crystals. The crystals were characterized by single crystal x-ray diffraction as well as measurements of magnetization, electrical transport, and heat capacity. The physical behaviors are generally similar to published results on crystals grown from a stoichiometric melt with two notable exceptions. The Sommerfeld coefficient is found to be 18 mJ/K2/mol, a little more than half of the previously reported value, and the Neel temperature is found to be 150 K, about 25K higher than in previous reports. The reason for these discrepancies are uncertain, but they may be related to differences in stoichiometry or disorder; it is expected that the Cr/Fe ratio has some variability in this compound. In addition, we find unusual thermal expansion behavior, with an anomaly at the Neel temperature and nearly temperature independent thermal expansion along the hexagonal c-axis above this transition. This suggests significant spin-lattice coupling, which may provide insight into non-metallic transport properties that have been associated with anomalous charge carrier scattering.
title Enhanced Neel temperature and unusual thermal expansion in flux-grown FeCrAs crystals
topic Materials Science
Strongly Correlated Electrons
url https://arxiv.org/abs/2505.21735