Abstract
In order to access the influence of the local environment on the structural and electronic properties of , we investigated the series of compounds by measuring electrical resistivity , thermal conductivity , Seebeck coefficient , as well as heat capacity as a function of temperature. For , all obtained quantities exhibit anomalous features near the structural transition temperature . For the nonstoichiometric compounds , these anomalies remain evident but appear to be weaker as increasing Al concentration. The corresponding transition temperature decreases with , indicating the suppression of the low-temperature tetragonal phase via Al doping in . 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 . In addition, several aspects regarding the structural and electronic properties were compared to those of other Heusler alloys.
1 More- Received 6 September 2004
DOI:https://doi.org/10.1103/PhysRevB.71.064202
©2005 American Physical Society