PREPARATION AND CHARACTERIZATION OF SOME COLOSSAL MAGNETO-RESISTANCE MATERIALS
A series of GMR materials with compositional formula Re 0.67 Sr 0.33 MnO 3, where Re = La, Nd, Sm, Gd, Pr, etc. and their combinations were prepared by the solid state reaction method. All the samples were characterized by the powder X-ray diffraction method and the patterns show that the samples are single phase with orthorhombic structure. Resistivity measurements were also carried out by the four probe method in the temperature range 80–300 K and from these results, Metal–Insulator (M–I) transition temperatures of the samples were obtained. Finally, the magneto-resistance measurements were also carried out as a function of magnetic field and temperature over a temperature range 80–300 K. It has been observed that the magneto-resistance of Lanthanum-based mixed compositions is better than that of pure compositions.