Magnetic field dependence of the resistance and magnetization of the giant magnetoresistive Pr0.7Ca0.25Sr0.05MnO3 polycrystalline sample

The Pr0.7Ca0.25Sr0.05MnO3 polycrystalline sample, which exhibits a huge negative magnetoresistive effect of 2 x 10(7)% at T-max = 88 K with B = 5 T, has been studied by coupling resistive (R(T) and R(B)) and magnetic (M(T) and M(B)) measurements. At T-max both R(B) and M(B) loops show an hysteretic behavior for B > 1 T but R and M return to their initial values when B is returned to 0. Our results suggest that a phase transition between two different magnetic states occurs for this sample close to T-max; this transition can be also induced by the application of a magnetic field of several tesla.