Structure and Properties of Manganese-Substituted Bismuth Titanates

Abstract

Partial substitution of manganese for titanium in bismuth titanate is a potential method to introduce ferromagnetic properties to ferroelectric bismuth titanate. We have established that manganese-substituted bismuth titanate forms only at low manganese contents. As the manganese content is increased, secondary phases form. A combination of neutron and synchrotron X-ray powder diffraction has been used to determine the structure of manganese-substituted bismuth titanates with chemical composition Bi4MnxTi3_xO12 (0 ≤ x ≤1 at 0.05 steps). Measurements between 4 K and 1073 K have been used to examine the phase transitions that they undergo. It was found the substitution of manganese into bismuth titanate increases the phase transition temperature to tetragonal by about 100 °C. Neutron diffraction and bulk magnetic susceptibility measurements demonstrate the absence of long-range magnetic cation ordering in selected examples.