GMR in Heusler Type Alloys Fe_<2+x>V_<1-x>Al : Condensed Matter: Electronic Properties, etc.

概要

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Electrical resistivity (ρ), magnetoresistance (MR) and magnetization (ρ) for Heusler type alloys Fe_<2+x>V_<1-x>Al with -0.10 <__= x <__= 0.20 were measured. A giant magnetoresistance (GMR) of about 40% was observed for the weakly inhomogeneous ferromagnet Fe_<2.1>V_<0.9>Al at 4.2 K in 130 kOe. In the ferromagnetic alloys (x >__= 0.10) the ρ showed a maximum near the Curie temperature (T_C) and the temperature coefficient of resistivity (TCR) was negative above T_C. For the paramagnetic alloys (x <__= 0.05) TCR was negative in the entire temperature (T) range examined. In the low T range, the alloys with x<__= 0.10 exhibited variable-range hopping (VRH) conduction behavior, ln ρ∝ T^<-1/4>. The magnetism of the present alloys was explained on the basis of the concept of magnetic clusters. The origin of the present GMR was discussed in relation to the Anderson localization of carriers in alloys having atomic and magnetic disorders.
社団法人日本物理学会の論文
2000-04-15