Giant magnetoresistance at 300 K in single crystals of La0.65(PbCa)0.35MnO3

Abstract

Giant magnetoresistance (GMR) at 300 K and 5.5 T with ΔR/R(0)=74% was observed in single crystals of La0.65(PbCa)0.35MnO3. The maximum GMR occurs exactly at the ferromagnetic–paramagnetic phase transition temperature (Tc). For T<Tc, the R(T) curve is closely related to the M(T) curve. A sign change in the curvatures of R(H) curves below and above Tc has been observed, indicating that two different mechanisms are responsible for the magnetic scatterings of the carriers in two separate temperature regions.