Anisotropic spin distribution and perpendicular magnetic anisotropy in the layered ferromagnetic semiconductor (Ba,K)(Zn,Mn)$_{2}$As$_{2}$

TL;DR

This study investigates the perpendicular magnetic anisotropy in the layered ferromagnetic semiconductor (Ba,K)(Zn,Mn)$_{2}$As$_{2}$, revealing anisotropic electron distribution and the origin of magnetic anisotropy through x-ray magnetic circular dichroism measurements.

Contribution

It provides the first detailed analysis of anisotropic spin distribution and the microscopic origin of magnetic anisotropy in (Ba,K)(Zn,Mn)$_{2}$As$_{2}$ using angle-dependent XMCD.

Findings

Large magnetic anisotropy with an anisotropy field of 0.85 T was observed.

Anisotropic distribution of Mn 3d electrons was identified, with specific orbital populations.

Magnetic anisotropy is linked to degeneracy lifting of hybridized states at the Fermi level.

Abstract

Perpendicular magnetic anisotropy of the new ferromagnetic semiconductor (Ba,K)(Zn,Mn)$_{2}$As$_{2}$ is studied by angle-dependent x-ray magnetic circular dichroism measurements. The large magnetic anisotropy with the anisotropy field of 0.85 T is deduced by fitting the Stoner-Wohlfarth model to the magnetic-field-angle dependence of the projected magnetic moment. Transverse XMCD spectra highlights the anisotropic distribution of Mn 3$d$ electrons, where the $d_{xz}$ and $d_{yz}$ orbitals are less populated than the $d_{xy}$ state because of the $D_{2d}$ splitting arising from the elongated MnAs$_{4}$ tetrahedra. It is suggested that the magnetic anisotropy originates from the degeneracy lifting of $p$-$d_{xz}$, $d_{yz}$ hybridized states at the Fermi level and resulting energy gain due to spin-orbit coupling when spins are aligned along the $z$ direction.