Dresden 2020 – scientific programme
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MA: Fachverband Magnetismus
MA 23: Functional Antiferromagnetism
MA 23.7: Talk
Tuesday, March 17, 2020, 11:00–11:15, HSZ 401
Tetragonal CuMnAs: Phase stability and finite temperature magnetism — •Karel Carva, Pavel Baláž, David Wagenknecht, and Klára Uhlířová — Charles University, DCMP, Ke Karlovu 5, CZ-12116, Prague, Czechia
The antiferromagnetic semimetal CuMnAs has a high application potential in spintronics. A controlled rotation of magnetic moments’ orientation by means of an applied electrical field has been demonstrated in tetragonal CuMnAs, employing spin-orbit torques. However, bulk CuMnAs natively crystallizes in the orthorhombic phase, which has different interesting properties. Tetragonal CuMnAs phase has been achieved in epitaxially deposited samples or by inserting lattice defects linked to non-stoichiometry in CuMnAs [1]. The tendency towards tetragonal phase with an increased Cu content has been confirmed by ab initio calculations [1].
We have estimated the stability of different phases and calculated formation energies of possible defects in the alloy. MnCu and CuMn antisites and vacancies on Mn or Cu sublattices were identified as most probable defects in CuMnAs. We estimated also the in-plane resistivity of CuMnAs with defects of low formation energies. Finally, we have determined the exchange interactions and estimated the Néel temperature of the ideal and disordered AFM-CuMnAs [2]. A good agreement with the experimental data makes it possible to estimate the structure and composition of real CuMnAs samples.
[1] K. Uhlířová et al., J. Alloys Compd. 771, 680 (2018)
[2] F. Máca et al., Phys. Rev. B 96, 094406 (2017)