Spin glass-like state, charge ordering, phase diagram and positive entropy change in Nd0.5-xPrxSr0.5MnO3 perovskites

Abstract

The mixed rare earth manganites Nd0.5-xPrxSr0.5MnO 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{greater than or slanted equal to}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 <rA>. 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. ?? 2006 Elsevier B.V. All rights reserved.