BARC/PUB/09/0546

 
  Evolution of ferromagneticlike order in Fe2V1-xCrx Al Heusler alloys  
     
 
Author(s)

Saha, R.; Srinivas, V.; Rao, T. V. C.

ABSTRACT

Structural, magnetic, and magnetotransport behaviors of Fe2V1−xCrxAl Heusler-type alloys have been investigated in the present work. From the detailed analysis of data it is observed that increasing Cr content promotes site disorder of Fe and Al, which in turn leads to destabilization of L21 superstructure of Fe2VAl. This site disorder seems to enhance the magnetic moment through spatially confined magnetic entities and intercluster interactions, transforming the alloy system into a magnetically ordered state in the limit x→1. Low-temperature magnetoresistance (MR) values drop quite rapidly from ~10% for x = 0 to 0.4% for x = 0.8, suggesting that magnetic interactions have a role in MR deterioration. Further the MR exhibits a maximum at a particular temperature in the vicinity of magnetic transition temperature, where interaction effects weaken. Our magnetization data support MR results and suggest that undoped Fe2VAl exhibits cluster-glass behavior with optimum super paramagnetic (SPM) contribution, developed possibly due to the random anisotropy with the presence of V. However, in Cr-substituted alloys anisotropy reduces due to coupling between the clusters, which, in turn, results in reduced SPM contribution and low MR values.

 
 
SIRD Digital E-Sangrahay