Mössbauer Spectroscopy Studies of Mechanosynthesized Fe2CrSi and Co2FeAl Heusler Alloys

K. Czarnackaa, P. Jaskółowskab, D. Oleszakb, M. Pękałac, E. Jartycha aLublin University of Technology, Department of Electronics and Information Technology, Nadbystrzycka 38A, 20-618 Lublin, Poland bWarsaw University of Technology, Faculty of Materials Science and Engineering, Wołoska 141, 02-507 Warsaw, Poland cWarsaw University, Chemistry Department, Żwirki i Wigury 101, 02-089 Warsaw, Poland

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Two Heusler alloys, i.e., Fe2CrSi and Co2FeAl, were successfully prepared using the mechanical alloying method. X-ray diffraction and Mössbauer spectroscopy were applied to monitor the process of alloy formation. In both cases, the disordered body-centered cubic solid solution was obtained after 20 h of milling, with an average crystallite size of 11 and 23 nm for Fe2CrSi and Co2FeAl, respectively. Thermal treatment caused an increase in grain size and the formation of Heusler phases. Mössbauer spectroscopy revealed atomic disorder in the occupation of the crystallographic positions in the L21 structure. Macroscopic magnetic measurements showed soft magnetic properties of the milled and annealed powders. The saturation magnetization values of 68 and 140 emu/g and magnetic moments of 2.33 and 5.14 μB/f.u. determined for, respectively, Fe2CrSi and Co2FeAl alloys correspond well with the average values of the hyperfine magnetic fields ~20 and ~31 T revealed by Mössbauer spectroscopy.

DOI:10.12693/APhysPolA.146.227 topics: Heusler alloys, mechanical alloying, Mössbauer spectroscopy, magnetization