La0.67Ca0.33MnO3薄膜中的各向异性应变与电荷有序  

ANISOTROPIC STRAIN AND CHARGE ORDERING IN La_(0.67)Ca_(0.33)MnO_3 FILMS

作　　者：李国民[1] 王凌飞[1] 黄振[1] 吴文彬[1] 

机构地区：[1]合肥微尺度物质科学国家实验室,中国科学技术大学,合肥230026

出　　处：《低温物理学报》2011年第1期10-14,共5页Low Temperature Physical Letters

基　　金：国家自然科学基金(项目编号:10874166,50721061);国家重点基础研究发展计划(项目编号:2006CB922005,2009CB929502)资助的课题~~

摘　　要：本文采用脉冲激光沉积法在NdGaO3(001)单晶衬底上制备了一系列的La0.67Ca0.33MnO3薄膜,实验主要研究了薄膜的输运性质.La0.67Ca0.33MnO3块材是铁磁金属基态,而La0.67Ca0.33MnO3/NdGaO3(001)薄膜由于各向异性应变的存在,可以观测到电荷有序绝缘相的出现.薄膜样品表现出明显的两相共存(铁磁金属态和电荷有序绝缘相),我们可以通过改变薄膜厚度和后退火时间来调制电荷有序绝缘相.在薄膜相共存区域,升降温过程中有显著的热滞现象,可以观测到明显的低场磁阻.结果表明各向异性应变对于锰氧化物薄膜中电荷有序相的形成有重要作用.Transport properties of La0.67Ca0.33MnO3 films grown on NdGaO3（001） substrates were systematically studied.The control of charge ordering insulating（COI） phase in epitaxial La0.67Ca0.33MnO3 / NdGaO3（001） thin films,with essentially the ferromagnetic metal ground state as observed for the bulk counterparts,has been realized via the anisotropic strain relaxation.These films show significant phase coexistence of ferromagnetic metallic state and charge ordering insulating state.By changing the film thickness and postannealing temperature,the COI phase can be tuned.A marked thermal hysteresis behavior has been observed and a huge low-field magnetoresistance（LFMR） was obtained in the epitaxial system.The LFMR that occurred in a wide temperature range makes the approach promising for device applications.The results demonstrate the crucial role of anisotropic strain in inducing the charge ordering insulating state in manganites films.

关 键 词：钙钛矿锰氧化物 电荷有序 应变 

分 类 号：O482.5[理学—固体物理]