Spin density in frustrated magnets under mechanical stress: Mn-based antiperovskites

TL;DR

This study investigates how mechanical stress influences the non-uniform spin density distribution in Mn-based antiperovskite compounds with frustrated magnetic structures, revealing strain-dependent changes in spin domain orientation and shape.

Contribution

It provides detailed analysis of spin density variations under mechanical strain in frustrated magnets, highlighting the complex non-uniform spin structures beyond simple models.

Findings

Spin density forms complex 'spin clouds' around atomic sites.

Strain reverses the orientation of spin domains.

Spin density depends on electronic state localization.

Abstract

In this paper we present results of our calculations of the non-collinear spin density distribution in the systems with frustrated triangular magnetic structure (Mn-based antiperovskite compounds, Mn_{3}AN (A=Ga, Zn)) in the ground state and under external mechanical strain. We show that the spin density in the (111)-plane of the unit cell forms a "domain" structure around each atomic site but it has a more complex structure than the uniform distribution of the rigid spin model, i.e. Mn atoms in the (111)-plane form non-uniform "spin clouds", with the shape and size of these "domains" being function of strain. We show that both magnitude and direction of the spin density change under compressive and tensile strains, and the orientation of "spin domains" correlates with the reversal of the strain, i.e. switching compressive to tensile strain (and vice versa) results in "reversal" of the domains. We present analysis for the intra-atomic spin-exchange interaction and the way it affects the spin density distribution. In particular, we show that the spin density inside the atomic sphere in the system under mechanical stress depends on the degree of localization of electronic states.