Effects of Mn substitution on ferro- and piezoelectric properties of Bi0.86Sm0.14FeO3 thin films

The Bi_0.86Sm_0.14FeO₃ (BSFO) and Bi_0.86Sm_0.14Fe_1 − xMn_xO₃ (BSFMO) (x = 0.01, 0.03, 0.05) thin films were deposited on indium tin oxide/glass substrates via a metal organic deposition method. 1 at.% Mn doping leads to an evident reduction of the leakage current in BSFO film. More importantly, the Bi_0.86Sm_0.14Fe_0.99Mn_0.01O₃ film exhibits the lowest coercive field (E_c = 272 kV/cm), the largest remanent polarization (P_r = 53.6 μc/cm²) and the remanent out-of-plane piezoelectric coefficient (d₃₃ = 146 pm/V). However, further increase of Mn doping content results in the deterioration of the charge retaining capability and the piezoelectric properties of the films. The negative influence of high Mn doping contents was discussed based on the structure change and the contribution of irreversible movement of non-180° domain walls in the aged films.