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

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 3d 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.