铁电磁体Pb(Fe_(1/2)Nb_(1/2))O_3相变特征  

PHASE TRANSITION CHARACTERS OF FERROELETROMAGNET Pb(Fe 1/2 Nb 1/2 )O 3 

作　　者：高兴森[1] 陈晓原[1] 殷江[1] 刘俊明[1] 刘治国[1] 

机构地区：[1]南京大学固体微结构物理国家重点实验室

出　　处：《物理学报》1999年第5期942-947,共6页Acta Physica Sinica

基　　金：国家攀登计划;国家863计划资助

摘　　要：借助与示差扫描量热法、磁化率测量、电子自旋共振、铁电与介电性质测量及电子衍射系统地研究了Ｐｂ（Ｆｅ１／２Ｎｂ１／２）Ｏ３（ＰＦＮ）的电、磁性质和相变特征．结果表明发生在３８０Ｋ附近的顺电－铁电转变和发生在１４５Ｋ附近的顺磁反铁磁转变分别为一级相变和二级相变或弱一级相变．在室温下，ＰＦＮ的剩余极化与矫顽场分别为１１５μＣ／ｃｍ２和３０４ｋＶ／ｃｍ．介电测量表明ＰＦＮ的顺电铁电相变为弥散型相变．其弥散指数为１６２．电子衍射表明Ｆｅ３＋与Ｎｂ５＋离子在Ｂ位置上是无序分布的，正是这种与无序分布相关联的成分涨落导致铁电相变的弥散性．Abstract Ferroeletromagnetic Pb(Fe 1/2 Nb 1/2 )O 3 (PFN) ceramics has been investigated systematically. Differential Scanning Calorimetric (DSC) analysis revealed that para ferroelectric transition at about 380K and para antiferromagnetic transition at about 145K were first order and weak first order or second order transition, respectively. Electronic Paramagnetic Resonance (EPR) indicated that above Néel temperature the resonance shows paramagnetic characters and under Néel temperature it shows antimagnetic characters .The spontaneous polarization and coercive field of PFN at room temperature are 11.5μC/cm 2 and 3.04kV/cm, respectively. Dielectric measurement showed that the para ferroelectric transition is diffusive character and the diffuse exponent is 1.62. Selected area electron diffraction pattern of PFN showed that the occupations of Fe 3+ and Nb 5+ ions in B site are disordered,leading to the diffuse characters of the para ferroelectric transition.

关 键 词：相变特征 铁电磁体 电磁性质 

分 类 号：TM221.014[一般工业技术—材料科学与工程]