薄膜厚度对1-3型BaTiO3-CoFe2O4多重铁性薄膜相变温度的影响

Effect of thickness on the critical phase transition temperature of 1-3 type BaTiO_3-CoFe_2O_4 multiferroic composite thin films

基于热动力学理论,通过对演化方程的线性稳定分析,确定了1-3型BaTiO3-CoFe2O4(BTO-CFO)多重铁性复合材料中的铁电、铁磁相变温度.考虑系统中基底与薄膜之间及薄膜内铁电相、铁磁相之间的内应力和外应力的弹性耦合,确立了顺电到铁电/铁磁地相变临界温度地解析式.临界温度与两相体积分数、基底、薄膜的晶格尺寸、薄膜两相的材料性能及薄膜厚度都有很大关系.两相的相变临界温度可以通过调节体积分数及薄膜厚度进行控制.

Based on the thermodynamic theory, the critical phase transition temperature of 1-3 type multiferroic composite BaTiO3-CoFe2O4 was investigated by linear stability analysis, Taking into account the coupled elastic stress on the interfaces of ferroelectric/ferromagnetic phases and film/substrate, the analytic expressions of para-ferro transition temperature of the epitaxial multiferroic composite thin film were derived as a function of volume fraction, lattices parameters, material constants and thin film thickness, The results show that the critical phase transition temperature can be controlled by adjusting the volume fraction or thickness of the composite thin film.