Electric-Field Tunability of Dielectric in Polycrystalline Sr1?xMnxTiO3 Thin Films
HOU Yan-Yan1, HE Ju1, XU Ting-Ting1, XIAO Shu-Yu1, LU Xue-Liang 1, HUANG Feng-Zhen1,2, LU Xiao-Mei1,2, ZHU Jin-Song1,2**
1National Laboratory of Solid State Microstructures and Physics School, Nanjing University, Nanjing 210093 2Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093
Abstract：The electric-field tunability of dielectric constant (ϵ–E) in Sr1?xMnxTiO3 films (x=0, 0.005, 0.010, 0.020 and 0.030) prepared by the metal organic decomposition method on Pt/Ti/SiO2/Si substrates is studied in the frequency range from 100 Hz to 1 MHz with different Mn contents at different temperatures. The frequency-independent tunability increases strongly with decreasing the temperature from 300 K to 150 K. The tunability (～31%) in thin films (x=0.005) at 150 K is obtained and the temperature for the same tunability in ceramics is about 60 K lower than the present one. This tunability is comparable with that in one of ferroelectric Sr1?1.5xBixTiO3 thin films. Similarly, the well-defined P(E) hysteresis loop and 2Pr (1.2 μC/cm2) can be obtained at 300 K in Sr1?xMnxTiO3 films with x=0.005. Both the existence of electric dipole or poled micro domain introduced by the doped Mn2+ located in the off-center position at Sr sites and the strain between the thin film and the substrate are the origins of the tunable and polar behavior in Sr1?xMnxTiO3 films.
2015, Vol. 32 
