A comparative structural, thermal and electrical study of Ca super(2+), Sr super(2+) substituted BiMnO sub(3)

Bi sub(1-x)A sub(x)MnO sub(3) (A = Sr, Ca; 0.40 < or = x < or = 0.55) systems have been synthesized by solid state reaction method to investigate the effect of two different cations substitution in place of Bi super(3+). All samples are monophasic as observed in X-ray diffraction. The Bi sub(1-x)Sr sub(x)MnO sub(3) shows the tetragonal symmetry whereas, Bi sub(1-x)Ca sub(x)MnO sub(3) shows orthorhombic as confirmed by Rietveld refinement. The Bi sub(1-x)Sr sub(x)MnO sub(3) system shows higher conductivity as compared to Bi sub(1-x)Ca sub(x)MnO sub(3). Bi sub(0.50)Sr sub(0.50)MnO sub(3) exhibits highest conductivity of 180 S/cm at 790 [degrees]C which can be attributed to its higher specific free volume and uniform grain size with better distribution in entire structure. Sr super(2+) doped system has lower thermal expansion coefficient as compared to Ca super(2+) doped system.