Structural, thermal, and electronic properties of Fe2VSi1-xAlx -: art. no. 064202

In order to access the influence of the local environment on the structural and electronic properties of Fe2VSi, we investigated the Fe2VSi1-xAlx series of compounds by measuring electrical resistivity (rho), thermal conductivity (kappa), Seebeck coefficient (S), as-well as heat capacity (C-p) as a function of temperature. For Fe2VSi, all obtained quantities exhibit anomalous features near the structural transition temperature T-s approximate to 123 K. For the nonstoichiometric compounds Fe2VSi1-xAlx, these anomalies remain evident but appear to be weaker as increasing Al concentration. The corresponding transition temperature T-s decreases with x, indicating the suppression of the low-temperature tetragonal phase via Al doping in Fe2VSi. Theoretical studies with ab initio calculations were also employed to investigate the present structural and magnetic phase transition. Both theoretical results and experimental observations consistently yield a possible disappearance of the structural transition beyond a critical concentration x(C) approximate to 0.25. In addition, several aspects regarding the structural and electronic properties were compared to those of other Heusler alloys.