A位掺杂Sr_(1-x)La_(2x/3)Bi_4Ti_4O_(15)陶瓷的铁电介电性能  

Ferroelectric and dielectric properties of Sr_(1-x)La_(2x/3)Bi_4Ti_4O_(15) ceramics

作　　者：王伟[1] 顾世浦[1] 单丹[1] 陈小兵[1] 

机构地区：[1]扬州大学物理科学与技术学院,江苏扬州225002

出　　处：《扬州大学学报（自然科学版）》2006年第4期38-41,共4页Journal of Yangzhou University：Natural Science Edition

基　　金：国家自然科学基金资助项目(10274066);江苏省自然科学基金资助项目(BK2005052)

摘　　要：Sr1-xLa2x／3Bi6TiO15（SLBT-x,x=0．00～O．75）陶瓷居里温度（tc）随掺杂量的增加而降低，显示掺杂导致晶格畸变减小，这是由于La^3＋取代Sr^2＋位而产生的A位空位弱化了相邻TiO6八面体的耦合作用所致．样品介电峰峰高随掺杂量增加而降低，峰形宽化．表现出弥散相变的特征，这是由于La^3＋和Sr^2＋离子半径的差异以及高掺杂量下La^3＋离子部分进入铋氧层所致．样品的剩余极化（2Pr）在掺杂量为0．3时增加到23.1×10^-2C·m^-2,同时矫顽场降低到79．6×10^5V·m^-1，高价掺杂所形成的偶极子缺陷使得样品铁电性能明显改善．Dielectric and ferroelectric properties of La-doped Sr1-xLa2x/2Bi4Ti4O15 （SLBT-x, x= 0.00- 0.75） ceramics were investigated. The temperature dependence of dielectric permittivity （ε） for SLBT- x shows the Curie temperature （tc） decreases with increasing La content, implying the relaxation of lattice distortion, meanwhile the peak of the ε-t curve decreases and broadens,indicating the dispersion of phase transition. The A-site vacancies induced by the substitution of La^3＋ for Sr^2＋ weakens the coupling between the neighboring TiO6 octahedra and gaves rise to the relief of lattice distortion. The broadening of dielectric peak may be attributed to the difference of ionic radii between La^3＋ and Sr^2＋ as well as the exchange of La^3＋ at A-site and Bi^3＋ at bismuth oxide layer. The hysteresis loops of SLBT-x shows the Ira-substitution increases the 2P, up to 23.1 × 10^-2 C ·m^-2 and loweres Ec down to 79.6 ×10^5 V · m^-1. It may be related to the dipole defects induced by aliovalent doping at A-site.

关 键 词：掺杂 剩余极化 居里温度 偶极子缺陷 

分 类 号：O482.54[一般工业技术—材料科学与工程] TM271[理学—固体物理]