Structural and Magnetic Properties Control of Pr 0.7 Ba 0.3 MnO 3 with Sr-Doping

Structural and magnetic properties of Sr-doped Pr 0.7 Ba 0.3 MnO 3 polycrystallines prepared by solid state reaction are presented. Samples were in monoclinic structure P 2 1 / n without structural phase transition when Ba was gradually replaced by Sr. Parameters a , b , and c of a unit cell monotonously decrease with increasing Sr content, while β angle has increased from 89.981° to 90.007°. The X-ray absorption spectra show the co-existence of Mn 3+ and Mn 4+ ions in materials and the number of Mn 4+ ions increases in the presence of Sr. The thermal magnetization data indicate that the Curie temperature shifts toward room temperature from 190, 210, 232 to 267 K with increasing Sr content x from 0 to 0.3.