1. High-resolution diffraction reveals magnetoelastic coupling and coherent phase separation in tetragonal CuMnAs
- Author
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Karigerasi, Manohar H., Kang, Kisung, Huang, Jeffrey, Peterson, Vanessa K., Rule, Kirrily C., Studer, Andrew J., Schleife, André, Huang, Pinshane Y., and Shoemaker, Daniel P.
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Condensed Matter - Materials Science - Abstract
Tetragonal CuMnAs was the first antiferromagnet where reorientation of the N\'eel vector was reported to occur by an inverse spin galvanic effect. A complicating factor in the formation of phase-pure tetragonal CuMnAs is the formation of an orthorhombic phase with nearly the same stoichiometry. Pure-phase tetragonal CuMnAs has been reported to require an excess of Cu to maintain a single phase in traditional solid state synthesis reactions. Here we show that subtle differences in diffraction patterns signal pervasive inhomogeneity and phase separation, even in Cu-rich Cu$_{1.18}$Mn$_{0.82}$As. From calorimetry and magnetometry measurements, we identify two transitions corresponding to the N\'eel temperature (T$_N$) and an antiferromagnet to weak ferromagnet transition in Cu$_{1.18}$Mn$_{0.82}$As and CuMn$_{0.964}$As$_{1.036}$. These transitions have clear crystallographic signatures, directly observable in the lattice parameters upon in-situ heating and cooling. The immiscibility and phase separation could arise from a spinoidal decomposition that occurs at high temperatures, and the presence of a ferromagnetic transition near room temperature warrants further investigation of its effect on the electrical switching behavior., Comment: 11 pages, 9 figures, added author middle initial, additional text and figures in supplementary, and resizing the figures
- Published
- 2022
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