Fe_2O_3对锌铁氧体隧道结构和磁性能的影响  

Influence of Fe_2O_3 on the tunnelling structure and magnetic properties of zinc ferrite

作　　者：张栋杰[1] 都有为[2] 

机构地区：[1]南京师范大学 [2]南京大学固体微结构国家实验室

出　　处：《材料研究学报》2004年第1期34-38,共5页Chinese Journal of Materials Research

基　　金：国家重点基础研究发展规划G1999064508;江苏高校自然科学研究计划03KJB430068资助项目.

摘　　要：利用X射线衍射和高分辨透射电镜(HRTEM)分析和观测了ZnFe2O4/Fe2O3纳米复相铁氧体的结构,研究了Fe2O3对ZnFe2O4/Fe2O3纳米复相铁氧体的结构和磁性能的影响.结果表明:过量的Fe2O3是在复相锌铁氧体内形成隧道结构和隧道磁电阻(TMR)的必要条件;在复相锌铁氧体中α-Fe2O3位于晶界处,形成隧道结构的绝缘层;复相锌铁氧体具有非线性的伏安曲线和TMR效应;单相锌铁氧体具有线性伏安曲线和一般铁氧体磁电阻效应;复相锌铁氧体的相变动力学表明α-Fe2O3是由晶界或表面控制的析晶.Two-phase nanostructure ZnFe2O4/Fe2O3 had been prepared by the sol-gel method and heat treatment. The structure was analyzed by X-ray diffraction (XRD) and high-resolution electron microscope (HREM). The results indicate that superfluous Fe2O3 composition is the necessary condition to form tunneling structure in two-phase ferrite. The tunneling structure was directly observed by HREM in two-phase ferrite, and the insulating layer of α-Fe2O3 was located in interface between ferrets. The two-phase ferrite has non-Ohmic character of Ⅰ-Ⅴ curve and tunneling magnetoresistance. The one-phase ferrite has linear-Ohmic character of Ⅰ-Ⅴ curve and small magnetoresistance of ferrite. Phase-transformation dynamics in two-phase ferrite show that crystallization of α-Fe2O3 is controlled by the interface or surface.

关 键 词：无机非金属材料 隧道结构 隧道磁电阻 铁氧体 ZNFE2O4 

分 类 号：O482[理学—固体物理]