La_0.7Sr_0.3MnO_3和ZnO异质结的量子铁磁自旋特性  

Antiferromagnetic Spin Quantum Characteristics of La_0.7 Sr_0.3 MnO_3 and ZnO Heterojunction

作　　者：任韧[1] 秦晓柯[1] 王卫人[1] 

机构地区：[1]西安交通大学,陕西西安710049

出　　处：《稀有金属材料与工程》2013年第1期140-144,共5页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(10775111);国家留学科研基金;西安交通大学新兴交叉项目(20100108);教育部重点实验室项目

摘　　要：采用脉冲激光沉积方法制备La0.7Sr0.3MnO3/ZnO异质结,并对其量子铁磁自旋行为进行研究。发现掺杂浓度可有效调整长程的电子自旋和轨道的相互作用,以及短程小极化子的相互作用程度。LSMO/ZnO异质结构可对能带进行有效剪裁。XRD结果表明,所制样品具有良好的晶格外延特性。伏安特性和阻温曲线显示异质结具有半金属光导特性。在激光光场和磁场下测试La0.7Sr0.3MnO3/ZnO异质结量子铁磁自旋磁阻及光阻。结果发现,样品x=0.3在Tp=250K发生金属绝缘体相变而呈现半金属特性,在Tc=175K温度发生顺磁到反铁磁相变。连续激光下低于峰值温度220K和脉冲激光下低于175K区域激光光场导致光致退磁,光阻增大,在大于峰值温度Tp的高温区出现光阻降低。研究表明,在光场下La0.7Sr0.3MnO3/ZnO异质结特性受界面电子自旋取向和载流子浓度调控,态密度以及自旋轨道作用会导致光致阻抗变化,这些影响与LSMO/ZnO异质结的极化和界面应力所产生的界面态缺陷结构有关。The La0.7Sr0. 3MnO3 and ZnO deposition films prepared by the pulse laser deposition on LAO （100） substrates were investigated The sample with different doped concentrations led to interaction between electron spins and orbital order, as well as short-range polaronic disorder. XRD patterns found that L1-xSrxMnO3 and ZnO diffraction peak had （100）, （200） and （002） dominant orientations. The multilayers films lattices were matched with each other. The V-1 properties and R-T curves show the heterojunction have half-metal optoelectronic conductivity properties. We measured the photoresistances and MR of LAO/La0.7Sr0.3MnO3/ZnO heterojunction in the optical and magnetic field respectively. The results indicate that the La0.TSr0.3MnO3 layer with x=0.3-0.4 exhibited the metal to insulator transition at Tp 250 K and paramagnetic to antiferromagnetic phase transition at Tc 175 K. The La0.TSr0.3MnO3/ZnO heterojunction realized quantum energy band clipping and rebuilt the energy band structure. The photoresistance with irradiation of pulsed and CW laser below Tp 220 K are increased. The results show that the changes of spin orientation, barriers concentration, state density and spin-orbit interactions led to photoresistance. The polarization and interface strain between La0.vSr0.3IV^nO3 and ZnO heterojunction occurred related with defect structure at dissipation layer interface

关 键 词：钙钛矿锰氧化合物 光电阻效应 异质结薄膜 电子自旋 铁磁半导体 

分 类 号：O614.331[理学—无机化学] O614.241[理学—化学]