Structural and electronic properties of Sr1−xCaxTi0.5Mn0.5O3

Abstract The series of Sr 1− x Ca x Ti 1/2 Mn 1/2 O 3 perovskites has been prepared using solid state methods and their structures determined using combination of synchrotron X-ray and powder neutron diffraction. At room temperature the crystal structure evolves with increasing Ca content from P m 3 ¯ m →tetragonal I 4 /mcm →orthorhombic Pbnm , as a consequence of the sequential introduction of cooperative tilting of the (Ti/Mn)O 6 octahedra. X-ray absorption measurements show the Mn is tetravalent in all oxides. Magnetic susceptibility measurements demonstrate all the oxides to be paramagnetic at room temperature, with a transition to a spin glass arrangement occurring at low temperatures. Electrical measurements prove that all the members are semiconductors and their activation energy increase with Ca doping amount.