中国物理B ›› 2019, Vol. 28 ›› Issue (4): 46101-046101.doi: 10.1088/1674-1056/28/4/046101

• CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES • 上一篇    下一篇

Off-axis electron holography of manganite-based heterojunctions: Interface potential and charge distribution

Zhi-Bin Ling(令志斌), Gui-Ju Liu(刘桂菊), Cheng-Peng Yang(杨成鹏), Wen-Shuang Liang(梁文双), Yi-Qian Wang(王乙潜)   

  1. College of Physics & State Key Laboratory, Qingdao University, Qingdao 266071, China
  • 收稿日期:2019-01-11 修回日期:2019-02-13 出版日期:2019-04-05 发布日期:2019-04-05
  • 通讯作者: Yi-Qian Wang E-mail:yqwang@qdu.edu.cn

Off-axis electron holography of manganite-based heterojunctions: Interface potential and charge distribution

Zhi-Bin Ling(令志斌), Gui-Ju Liu(刘桂菊), Cheng-Peng Yang(杨成鹏), Wen-Shuang Liang(梁文双), Yi-Qian Wang(王乙潜)   

  1. College of Physics & State Key Laboratory, Qingdao University, Qingdao 266071, China
  • Received:2019-01-11 Revised:2019-02-13 Online:2019-04-05 Published:2019-04-05
  • Contact: Yi-Qian Wang E-mail:yqwang@qdu.edu.cn

摘要:

The interfacial electrical potentials and charge distributions of two manganite-based heterojunctions, i.e., La0.67Ca0.33MnO3/SrTiO3:0.05 wt% Nb (LCMO/STON) and La0.67Ca0.33MnO3/LaMnO3/SrTiO3:0.05 wt% Nb (simplified as LCMO/LMO/STON), are studied by means of off-axis electron holography in a transmission electron microscope. The influences of buffer layer on the microstructure and magnetic properties of the LCMO films are explored. The results show that when a buffer layer of LaMnO3 is introduced, the tensile strain between the STON substrate and LCMO film reduces, misfit dislocation density decreases near the interfaces of the heterojunctions, and a positive magnetoresistance is observed. For the LCMO/STON junction, positive and negative charges accumulate near the interface between the substrate and the film. For the LCMO/LMO/STON junction, a complex charge distribution takes place across the interface, where notable negative charges accumulate. The difference between the charge distributions near the interface may shed light on the observed generation of positive magnetoresistance in the junction with a buffer layer.

关键词: La0.67Ca0.33MnO3 films, electron holography, magnetic properties, interfacial electrical potential, charge distribution

Abstract:

The interfacial electrical potentials and charge distributions of two manganite-based heterojunctions, i.e., La0.67Ca0.33MnO3/SrTiO3:0.05 wt% Nb (LCMO/STON) and La0.67Ca0.33MnO3/LaMnO3/SrTiO3:0.05 wt% Nb (simplified as LCMO/LMO/STON), are studied by means of off-axis electron holography in a transmission electron microscope. The influences of buffer layer on the microstructure and magnetic properties of the LCMO films are explored. The results show that when a buffer layer of LaMnO3 is introduced, the tensile strain between the STON substrate and LCMO film reduces, misfit dislocation density decreases near the interfaces of the heterojunctions, and a positive magnetoresistance is observed. For the LCMO/STON junction, positive and negative charges accumulate near the interface between the substrate and the film. For the LCMO/LMO/STON junction, a complex charge distribution takes place across the interface, where notable negative charges accumulate. The difference between the charge distributions near the interface may shed light on the observed generation of positive magnetoresistance in the junction with a buffer layer.

Key words: La0.67Ca0.33MnO3 films, electron holography, magnetic properties, interfacial electrical potential, charge distribution

中图分类号:  (Electron holography)

  • 61.05.jp
68.37.-d (Microscopy of surfaces, interfaces, and thin films) 68.37.Og (High-resolution transmission electron microscopy (HRTEM)) 75.70.Cn (Magnetic properties of interfaces (multilayers, superlattices, heterostructures))