缺氧La_(1-x)Na_xMnO_(2.825)体系磁电性质  

Magnetic and electrical properties of La_(1-x)Na_xMnO_(2.825) system with oxygen deficiency

作　　者：刘宁[1] 郭焕银[1] 严国清[1] 唐永刚[1] 

机构地区：[1]宿州学院物理系

出　　处：《功能材料与器件学报》2008年第4期735-741,共7页Journal of Functional Materials and Devices

基　　金：国家自然科学基金重点项目(No.19934003);国家重点基础研究发展规划项目(No.001CB610604);安徽省教育厅自然科学研究项目(No.2006KJ266B;No.ZD2007003-1)资助

摘　　要：利用提高固相反应法烧结温度的方法制备了La1-xNaxMnO2.825(x=0.05,0.10,0.15,0.20)缺氧体系,测量了样品的XRD谱、红外光谱、拉曼光谱、M-T曲线、ESR谱线、ρ-T曲线。实验结果表明:与La1-xNaxMnO3体系相比,缺氧体系的磁化强度变小,居里温度Tc下降,出现了多相共存现象,原因是缺氧造成的Mn3+/Mn4+的比例变化,以及样品中氧含量的不均匀性;缺氧体系的电阻率升高,大部分样品表现为绝缘态,原因是氧空位引起的晶格作用、自旋作用与Mn3+/Mn4+的双交换作用的共同竞争。La1-xNaxMnO2.825 （x = 0.05, 0. 10, 0. 15, 0.20） system with oxygen deficiency was prepared by the solid - state reaction method with high - temperature sintering. XRD patterns, infrared spectra, Raman spectra, M - T curves, ESR curves and p - T curves of the samples were measured. The experi- mental results show that compared with La1-xNaxMnO3 system, in this system, the magnetization value becomes smaller, the Curie temperature TC decreases, and the phase separation appears, because the oxygen deficiency changes the Mn^3＋/Mn^4＋ proportion and the oxygen concentration in the samples is inhomogeneous; the resistivity of the system increases, and most samples exhibit the insulator state, because of the competition among the lattice function, the spin function induced by the oxygen vacancy, and the double - exchange function of Mn^3＋/Mn^4＋.

关 键 词：高温烧结 氧缺位 磁结构 输运行为 

分 类 号：O482.54[一般工业技术—材料科学与工程]