LAUSR

Abstract In this study, new all-d-metal Heusler alloys Fe50−xCr25+xV25 (x = 0–25) were investigated on the behaviors of atomic configuration, lattice constant change, and ferromagnetism from the aspects of theoretical calculations and experiments. The theoretical calculations found that both end-member compounds Fe50Cr25V25 (x = 0) and Cr50Fe25V25 (x = 25) prefer to crystallize in Hg2CuTi-type (space group: 216) structure rather than Cu2MnAl-type (space group: 225) one. During the whole substitution process, the structure of Fe50−xCr25+xV25 alloys remains Hg2CuTi-type structure, taking the path from 216 to 216, but with different degrees of BC-site disorder. Both the experimental and theoretical results reveal that the lattice constant increases first, and then abnormally decreases, showing a maximum at Cr40, due to the enhanced covalent d-d hybridizations between the transition metals. The magnetic moment and Curie temperature tuned by Cr substitution vary remarkably between 3.3 and 1.15 μB/f.u. and between 700 and 170 K, respectively, which indicates that the Cr substitution for Fe alters the spin polarizations and exchange interactions in the system. These results provide new insights into the atomic configuration, magnetism and bonding effect in all-d-metal Heusler alloys based on the d-d hybridizations.