The role of 3d electrons in the appearance of ferromagnetism in the antiferromagnetic Ru2MnGe Heusler compound: a magnetic Compton scattering study.

The antiferromagnetism in Ru2MnGe can be suppressed by the substitution of V by Mn and ferromagnetism appears. Synchrotron-based magnetic Compton scattering experiments are used in order to investigates the role of 3d electrons in the indirect/direct exchange interactions for the appearance of ferromagnetism. A small spin moment for the itinerant electron part on the magnetic Compton profile indicates that the metallic ferromagnet Ru2Mn0.5V0.5Ge has a weak indirect exchange interaction between the d-like and sp-like (itinerant) electrons. This suggests that the appearance of ferromagnetism is caused by the enhancement of the direct exchange interactions between d-d electrons in the Ru2MnGe Heusler compound. These findings indicate that the indirect exchange interaction between itinerant electrons and localized electrons is a significant key point for the appearance of ferromagnetism in this system.