Magnetic And Electronic Structure Studies Of Nanocrystalline (co2mn)40ni60 Alloy

Résumé: Nanocrystalline (Co2Mn)40Ni60 (wt%) alloy powder was prepared by high-energy ball milling under an argon atmosphere. Structure, microstructure, and magnetic properties were investigated by means of X-ray diffraction, scanning electron microscopy, and vibrating sample magnetometry. The X-ray diffraction analysis indicates that after 30 h of milling, a highly disordered (Co, Mn, Ni) solid solution emerges, having an average crystallite size of around 60 nm and a lattice parameter of about 3.5411 Å. Magnetization-field curves indicate the existence of ferromagnetic behavior irrespective of the milling time with a low hysteresis loop, a typical characteristic of a soft magnetic material. The magnetic properties, however, are found to be sensitive to the milling time: i.e. the ratio Mr=Msat manifests the formation of multi-domains magnetic structure. Diverse magnetic parameters were acquired from the approach to magnetic saturation. The electronic structure of the ferromagnetic (Co2Mn)40Ni60 alloy performed by self-consistent ab initio calculations based on the Korringa–Kohn–Rostocker method combined with the coherent potential approximation, reveals that the total DOS is mainly due to the 3d-like states of the constituent elements Mn, Co and Ni.

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