Disentangling the Mn moments on different sublattices in the half-metallic ferrimagnet Mn3−xCoxGa

Ferrimagnetic ${\text{Mn}}_{3-x}{\text{Co}}_x\text{Ga}$ compounds have been investigated by magnetic circular dichroism in x-ray absorption (XMCD). Compounds with $x>0.5$ crystallize in the ${\text{CuHg}}_2\text{Ti}$ structure. A tetragonal distortion of the cubic structure occurs for $x\le 0.5$ . For the cubic phase, magnetometry reveals a linearly increasing magnetization of $2x$ Bohr magnetons per formula unit obeying the generalized Slater–Pauling rule. XMCD confirms the ferrimagnetic character with Mn atoms occupying two different sublattices with antiparallel spin orientation and different degrees of spin localization and identifies the region $0.6<x\le 0.8$ as most promising for a high spin polarization at the Fermi level. Individual Mn moments on inequivalent sites are compared to theoretical predictions.