Spin glass-like state, charge ordering, phase diagram and positive entropy change in Nd 0.5−xPr xSr 0.5MnO 3 perovskites

Abstract

The mixed rare earth manganites Nd 0.5− x Pr x Sr 0.5MnO 3 ( x=0.1–0.5) have been prepared using solid state reaction technique. All samples are of single phase with orthorhombic structure. The microstructure of the samples was determined by SEM. The field-cooled (FC) and zero-field-cooled (ZFC) curves showed that samples with x⩾0.25 exhibit the spin glass-like state at low field and low temperatures, whereas, in the samples with x<0.25, there is the charge ordering (coexisting with FM–AFM transition) established at low temperatures. The Curie temperature of the samples increases with increasing Pr content due to increase of < r A>. Interesting feature is that at the FM–AFM transition region, the magnetic entropy change has positive value, in contrary to that at FM–PM transition region. The electrical property of the samples from 10 K to room temperature is examined in detail.