  Epitaxial thin films of the half-metallic Xa-compound Mn2CoGa (Hg2CuTi
prototype) were prepared by dc magnetron co-sputtering with different heat
treatments on MgO (001) substrates. High-quality films with a bulk
magnetization of 1.95(5)\mu_B per unit cell were obtained. The L3,2 x-ray
magnetic circular dichroism spectra agree with calculations based on density
functional theory (DFT) and reveal the antiparallel alignment of the two
inequivalent Mn moments. X-ray magnetic linear dichroism, in good agreement
with theory as well, allows to distinguish between itinerant and local Mn
moments. Based on non-collinear spin DFT it is shown that one of the two Mn
moments has local character, whereas the other Mn moment and the Co moment are
itinerant.
