【摘要】 用变温X射线及热分析等方法研究Bi₄Ti₃O₁2铁电薄膜的相变,结果表明,在温度为350⁴45℃之间,薄膜经历由烧绿石相向钙钛矿相的结构相变,在670℃附近,薄膜由铁电相向顺电相转变;该相变是由于晶格畸变量b/a随温度上升连续减小,使得薄膜晶体对称性发生改变引起,在相变点附近未观察到潜热的产生。更多还原

【Abstract】 Phase transition of Bi4Ti3O12(BTO) ferroelectric films were analyzed by x-ray diffraction and thermal analysis methods. The results indicate that the film transforms from the pyrochlore phase to the perovskite phase in the temperature range of 350-445℃ and transforms from the ferroelectric phase to the paraelectric phase at the 670℃. The ferro-para phase transition was brought about by continuous decrease of the orthorhombic distortion ( b/a ) which led the symmetry of the structure to be tetragonal. In the vicinity of phase transition point, no latent heat was observed.更多还原