GMR in Heusler type alloys Fe2+xV1-xAl

Electrical resistivity (rho), magnetoresistance (MR) and magnetization (sig ma) for Heusler type alloys Fe2+xV1-xAl with -0.10 less than or equal to x less than or equal to 0.20 were measured. A giant magnetoresistance (GMR) o f about 40% was observed for the weakly inhomogeneous ferromagnet Fe2.1V0.9 Al at 4.2 K in 139 kOe. In the ferromagnetic alloys (x greater than or equa l to 0.10) the rho showed a maximum near the Curie temperature (T-C) and th e temperature coefficient of resistivity (TCR) was negative above T-C. For the paramagnetic alloys (x less than or equal to 0.05) TCR was negative in the entire temperature (T) range examined. Tn the low T range, the alloys w ith x less than or equal to 0.10 exhibited variable-range hopping (VRH) con duction behavior, ln rho proportional to T-1/4. The magnetism of the presen t alloys was explained on the basis of the concept of magnetic clusters. Th e origin of the present GMR was discussed in relation to the Anderson local ization of carriers in alloys having atomic and magnetic disorders.