Microstructure and frequency dependent electrical properties of Mn-substituted BiFeO3 thin films

Abstract

Mn-substituted (0–10at.%) BiFeO3 (BFO) thin films were fabricated by chemical solution deposition on Pt∕Ti∕SiO2∕Si substrate. X-ray diffraction analysis revealed that no secondary phase appeared even if Fe atoms were substituted with Mn atoms up to 10at.%. However, in the 10at.% Mn-substituted BFO film, the lattice parameters decreased by approximately 0.6%. Substitution of small amount of Mn atoms such as 3–5at.% in BFO films was effective in reducing the leakage current density at a high electric field. The P-E (polarization versus electric field) hysteresis loops were measured by changing frequencies of triangular voltage pulses from 1to100kHz. In Mn-substituted BFO films, frequency dependences of the remanent polarization were not pronounced in the range from 10to100kHz and these measurements showed that the remanent polarization increased with increase of the Mn concentration.