inverse-heusler mn2fesi alloy prepared by powder metallurgy route

Abstract

The Mn2FeSi inverse-Heusler alloy was prepared by solid-state reactions using ball milling for 168 h in nhexane. Two milling procedures varying in the ball-to-powder ratio, namely 4:1 and 10:1, were used to follow their influence on alloy formation and its physical properties. In both cases no Heusler structure was obtained directly and therefore the subsequent annealing at 1223 K for 1.5 h in pure Ar was applied. The energydispersive X-ray analysis resulted in the chemical composition about 49.0-49.9 at% Mn, 25.3-25.6 at% Fe, and 24.8-25.4 at% Si, in a good agreement with nominal one. X-ray diffraction of both powders confirmed inverse-Heusler XA structure of lattice parameters 0.5675 nm (4:1) and 0.5677 nm (10:1), only slightly higher as theoretically obtained 0.560 nm. The presence of minor oxidation phases was also observed in the particle structure of powders. Magnetic properties were analysed at low and room temperatures. Both alloys exhibit paramagnetic behaviour at room temperature confirmed by transmission Mössbauer spectroscopy measurements. Different magnetic behaviour of alloys is observed below 65 K.