Spatial confinement tuning of quenched disorder effects and enhanced magnetoresistance in manganite nanowires  

作　　者：Yang Yu Qiang Li Qian Shi YinYan Zhu HanXuan Lin Hao Liu HongYan Chen Tian Miao Yu Bai YanMei Wang WenTing Yang WenBin Wang HangWen Guo LiFeng Yin Jian Shen 

机构地区：[1]State Key Laboratory of Surface Physics and Department of Physics,Fudan University,Shanghai 200433,China [2]Institute for Nanoelectronic Devices and Quantum Computing,Fudan University,Shanghai 200433,China [3]Collaborative Innovation Center of Advanced Microstructures,Nanjing 210093,China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2020年第3期106-111,共6页中国科学：物理学、力学、天文学（英文版）

基　　金：the National Key Research and Development Program of China(Grant No.2016YFA0300702);the Shanghai Municipal Natural Science Foundation(Grant Nos.19ZR1402800,18JC1411400,18ZR1403200,and 17ZR1442600);the Program of Shanghai Academic Research Leader(Grant Nos.18XD1400600,and 17XD1400400);the China Postdoctoral Science Foundation(Grant Nos.2016M601488,and 2017T100265)。

摘　　要：Complex oxides have rich functionalities and advantages for future technologies.In many systems,quenched disorder often holds the key to determine their physical properties,and these properties can be further tuned by chemical doping.However,understanding the role of quenched disorder is complicated because chemical doping simultaneously alters other physical variables such as local lattice distortions and electronic and magnetic environments.Here,we show that spatial confinement is an effective approach to tuning the level of quenched disorder in a complex-oxide system while leaving other physical variables largely undisturbed.Through the confinement of a manganite system down to quasi-one-dimensional nanowires,we observed that the nature of its metal-insulator phase transition exhibits a crossover from a discontinuous to a continuous characteristic,in close accordance with quenched disorder theories.We argue that the quenched disorder,finite size,and surface effects all contribute to our experimental observations.Noticeably,with reduced nanowire width,the magnetoresistance shows substantial enhancement at low temperatures.Our findings offer new insight into experimentally tuning the quenched disorder effect to achieve novel functionalities at reduced dimensions.Complex oxides have rich functionalities and advantages for future technologies. In many systems, quenched disorder often holds the key to determine their physical properties, and these properties can be further tuned by chemical doping. However,understanding the role of quenched disorder is complicated because chemical doping simultaneously alters other physical variables such as local lattice distortions and electronic and magnetic environments. Here, we show that spatial confinement is an effective approach to tuning the level of quenched disorder in a complex-oxide system while leaving other physical variables largely undisturbed. Through the confinement of a manganite system down to quasi-one-dimensional nanowires, we observed that the nature of its metal-insulator phase transition exhibits a crossover from a discontinuous to a continuous characteristic, in close accordance with quenched disorder theories. We argue that the quenched disorder, finite size, and surface effects all contribute to our experimental observations. Noticeably, with reduced nanowire width, the magnetoresistance shows substantial enhancement at low temperatures. Our findings offer new insight into experimentally tuning the quenched disorder effect to achieve novel functionalities at reduced dimensions.

关 键 词：quenched DISORDER MANGANITE NANOWIRES PHASE TRANSITION colossal MAGNETORESISTANCE 

分 类 号：TQ137.12[化学工程—无机化工] TB383.1[一般工业技术—材料科学与工程]