PLT10纳米晶材料结构和性能的研究

Study on Effect of Lanthanum-Modified Lead Titanate Nanocrystals

本文用硬脂酸凝胶法合成了ＰＬＴ１０纳米晶，研究了粒径对微观结构和介电性能的影响。结果表明，随着粒径的减少，ＰＬＴ１０在室温下由四方相转变为立方相，晶胞参数发生明显变化。铁电－顺电相变温度随粒径的减少而增加；当粒子尺寸小于２０ｎｍ时，相变消失。室温介电常数也随粒径呈规律性变化。

Lanthanum-modified lwad titanate(La content of 10 at%)nanocrystalline powderswere synthesized by stearic acid gel method,usingstearic acid,lead acetate,lanthanum nitrate and te-trabutyl titanate,the synthesis temperature was450℃,The nanocrystals were characterized bytransmission electron microscope(TEM)and X-ray diffraction ( XRD).The size efect of thenanocrystals on microstructure and ferroelectricproperties was investigated.The Curie temperatureT_c increases with decreasing grain size. When thegrain size is less than 19.4nm,the dielectric Peak ofphase transition disappears. The dielectric constantat room temperature increases sharply with increasein grain size,reaches a maximum at about 21 nm,and decreases with further increase in grain size.