Bi doping effects on the physical properties of Pr0.6Sr0.4Mn1-xBixO3 (0≤x≤0.2) manganese oxides

Structural, magnetic and magneto-caloric properties of Pr0.6Sr0.4Mn1-xBixO3 (0 <= x <= 0.2) powder samples have been investigated. X-ray powder diffraction showed that all our synthesized samples are single phase and crystallize in the orthorhombic symmetry with Pbnm space group. The unit cell volume increases with increasing Bi content. Bi doping leads to a weakening of the ferromagnetic (FM) ordering at low temperature, the Curie temperature T-c decreases from 3 10 K for x = 0.0 to 225 K for x = 0.2. The critical exponent gamma deduced from the M(H) curves is found to be gamma = 0.33 for Pr0.6Sr0.4Mn0.9Bi0.1O3 sample. A large magneto-caloric effect has been detected with a maximum of magneto-entropy change, vertical bar Delta S-max vertical bar, of 0.95 and 2 J/kg K at 1 and 8 T, respectively, at 255 K for a Bi doping amount of 0.1. (c) 2006 Elsevier B.V. All rights reserved.