Effects of Mn doping on the polarization and leakage current properties in Bi4Ti3O12 single crystals

Single crystals of Bi4Ti3O12 and Bi4Ti2.97Mn0.03O12−δ (Mn-BiT) were grown in air by a self-flux method, and the leakage current and polarization properties at 25 °C have been investigated along the a axis direction. The substitution of Mn at the Ti site is shown to be effective for suppressing leakage current. Mn-BiT crystals exhibits a leakage current density (∼10−8 A/cm2) by about two orders of magnitude lower than that of BiT crystals. Electron spin resonance measurements demonstrate that valence increase of Mn during the subsequent annealing in air plays an essential role in the low leakage current property. A superior polarization property (remanent polarization of 38 μC/cm2 and coercive field of 25 kV/cm) was obtained for Mn-BiT crystals.