Size effect on magnetic phase coexistence in Pr_0.5Sr_0.5Mn_1-xCr_xO₃

Abstract

Magnetic and transport properties are investigated in Pr_0.5Sr_0.5Mn_1-xCr_xO₃ (0 ⩽ x ⩽ 0.05) focusing on the effect of Cr substitution and particle size dependence. The studies demonstrate that magnetic and transport properties are significantly different for nanocrystalline compound from the bulk. Neutron depolarization and diffraction studies confirm that different fractions of magnetic phase separation between antiferromagnetic and ferromagnetic components, and ferromagnetic domain size give rise to the different magnetic and transport properties. Intriguingly, nanocrystalline compound with x = 0.05 shows apparent signature of arrested state in magnetization and magnetoresistance both in thermal and magnetic field variations which is absent in the bulk counterpart. A spin-glass like state is identified for nano at low temperature, which is argued to be correlated with the arrested or pinning mechanism.