La掺杂诱发层状钙钛矿型铁电体弛豫性相变的介电研究  

Dielectric study on relaxor-like phase transition of lanthanum doped bismuth layer-structured ferroelectrics

作　　者：惠荣[1] 朱骏[1] 卢网平[1] 毛翔宇[1] 羌锋[1] 陈小兵[1] 

机构地区：[1]扬州大学物理科学与技术学院,扬州225002

出　　处：《物理学报》2004年第1期276-281,共6页Acta Physica Sinica

基　　金：国家自然科学基金 (批准号 :10 2 740 66);江苏省教育厅自然科学基金 (批准号 :0 1KJB14 0 0 11)资助的课题~~

摘　　要：制备了La掺杂层状钙钛矿铁电体材料SrBi4 Ti4 O1 5,Sr2 Bi4 Ti5O1 8以及共生结构Bi4 Ti3O1 2 SrBi4 Ti4 O1 5,通过研究样品的变温介电特性发现 ,SrBi4 -xLaxTi4 O1 5(x=1 0 ) ,Sr2 Bi4 -xLaxTi5O1 8(x≥ 0 5 ) ,(Bi,La) 4Ti3O1 2 Sr(Bi,La) 4Ti4 O1 5(x=1 5 0 )样品的介电常数随温度变化曲线都具有弛豫性相变特征 ,La含量的变化对介电温度特性曲线有重要影响 ,随着La含量的增加 ,其弛豫程度明显增加 .弛豫的起源与La离子的存在引起局域出现的微畴有关 ,而正常铁电体—弛豫铁电体自发相变相对应的微观机理是正常铁电体的宏畴向弛豫铁电体微畴的转变 .Lanthanum doped bismuth layer-structured ferroelectrics and its intergrowth type, SrBi 4-x La x Ti 4O 15 , Sr 2La x Bi 4-x Ti 5O 18 , and (Bi,La) 4Ti 3O 12 -Sr(Bi,La) 4Ti 4O 15 , have been prepared by solid-state reaction method. The dielectric properties of those materials are measured. The results show that SrBi 4-x La x Ti 4O 15 ( x =1.0), Sr 2La x Bi 4-x Ti 5O 18 ( x ≥0 5), (Bi,La) 4Ti 3O 12 -Sr(Bi,La) 4Ti 4O 15 ( x =1 50) exhibit typical relaxational characteristics. The degree of diffuseness and relaxation increased with increasing La + {3+ } content. The origin of relaxation is the microdomain induced by La + {3+ } doing. The micromechanism corresponding to the transition between normal ferroelectrics and relaxors is explained as the transition from the macrodomain of normal ferroelectrics to the microdomain of relaxors.

关 键 词：镧掺杂 层状钙钛矿 铁电体 介电性能 弛豫性相变 介电常数 正常铁电体 弛豫铁电体 

分 类 号：O482.4[理学—固体物理]