We have calculated the spontaneous polarization $P_s$ of ferroelectric Na_0.5Bi_0.5TiO${}_3$ (NBT) thin films. $P_s$ increases with decreasing film thickness due to size and surface effects. It increases with increasing Dy and Nd ion doping and decreases by Er and Ho ion doping due to the different strain caused by the difference in the doping and host ion radii. Transition metal ion doping leads to appearance of ferromagnetism, i.e. of multiferroic properties at room temperature. The temperature dependence of the dielectric constant ${ϵ}^{\prime }$ shows anomalies at both temperatures, $T_d$ and $T_m$. ${ϵ}^{\prime }$ decreases with increasing magnetic field. The critical exponents $\gamma$, $\beta$ and $\delta$ are observed for bulk and thin film NBT. The value of $\gamma$ = 1.55 confirms the relaxor behavior of NBT.

我们计算了自发极化 ${磷}_{秒}$铁_0.5 Na _0.5 Bi _0.5 TiO的制备${}_3$ （NBT）薄膜。 ${磷}_{秒}$由于尺寸和表面效应，随着薄膜厚度的减小而增加。它随着 Dy 和 Nd 离子掺杂的增加而增加，并且由于掺杂和宿主离子半径的差异导致不同的应变而随着 Er 和 Ho 离子掺杂而减少。过渡金属离子掺杂导致铁磁性的出现，即在室温下具有多铁性。介电常数的温度依赖性${\epsilon }^{\prime }$ 在两种温度下都显示异常， ${吨}_d$ 和 ${吨}_{米}$. ${\epsilon }^{\prime }$随磁场增加而减小。关键指数$\gamma$, $\beta$ 和 $\delta$观察到块状和薄膜 NBT。的价值$\gamma$ = 1.55 证实了 NBT 的弛豫行为。