中国物理B ›› 2013, Vol. 22 ›› Issue (4): 47505-047505.doi: 10.1088/1674-1056/22/4/047505

所属专题: TOPICAL REVIEW — Magnetism, magnetic materials, and interdisciplinary research

• SPECIAL TOPIC --- Non-equilibrium phenomena in soft matters • 上一篇    下一篇

Reactively sputtered Fe3O4-based films for spintronics

李鹏, 金朝, 米文博, 白海力   

  1. Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Institute of Advanced Materials Physics, Faculty of Science, Tianjin University, Tianjin 300072, China
  • 收稿日期:2013-03-01 出版日期:2013-03-01 发布日期:2013-03-01
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 51272174) and the Natural Science Foundation of Tianjin City (Grant No. 12JCYBJC11100).

Reactively sputtered Fe3O4-based films for spintronics

Li Peng (李鹏), Jin Chao (金朝), Mi Wen-Bo (米文博), Bai Hai-Li (白海力)   

  1. Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Institute of Advanced Materials Physics, Faculty of Science, Tianjin University, Tianjin 300072, China
  • Received:2013-03-01 Online:2013-03-01 Published:2013-03-01
  • Contact: Bai Hai-Li E-mail:baihaili@tju.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 51272174) and the Natural Science Foundation of Tianjin City (Grant No. 12JCYBJC11100).

摘要: Half metallic polycrystalline, epitaxial Fe3O4 films and Fe3O4-based heterostructures for spintronics were fabricated by DC reactive magnetron sputtering. Large tunneling magnetoresistance was found in the polycrystalline Fe3O4 films and attributed to the insulating grain boundaries. The pinning effect of the moments at the grain boundaries leads to a significant exchange bias. Frozen interfacial/surface moments induce weak saturation of the high-field magnetoresistance. The films show a moment rotation related butterfly-shaped magnetoresistance. It was found that in the films, natural growth defects, antiphase boundaries, and magnetocrystalline anisotropy play important roles in high-order anisotropic magnetoresistance. Spin injection from Fe3O4 films to semiconductive Si and ZnO was measured to be 45% and 28.5%, respectively. The positive magnetoresistance in the Fe3O4-based heterostructures is considered to be caused by a shift of the Fe3O4 eg ↑ band near the interface. Enhanced magnetization was observed in Fe3O4/BiFeO3 heterostructures experimentally and further proved by first principle calculations. The enhanced magnetization can be explained by spin moments of the thin BiFeO3 layer substantially reversing into a ferromagnetic arrangement under a strong coupling that is principally induced by electronic orbital reconstruction at the interface.

关键词: reactively sputtered Fe3O4 films, spintronics, magnetoresistance, interface

Abstract: Half metallic polycrystalline, epitaxial Fe3O4 films and Fe3O4-based heterostructures for spintronics were fabricated by DC reactive magnetron sputtering. Large tunneling magnetoresistance was found in the polycrystalline Fe3O4 films and attributed to the insulating grain boundaries. The pinning effect of the moments at the grain boundaries leads to a significant exchange bias. Frozen interfacial/surface moments induce weak saturation of the high-field magnetoresistance. The films show a moment rotation related butterfly-shaped magnetoresistance. It was found that in the films, natural growth defects, antiphase boundaries, and magnetocrystalline anisotropy play important roles in high-order anisotropic magnetoresistance. Spin injection from Fe3O4 films to semiconductive Si and ZnO was measured to be 45% and 28.5%, respectively. The positive magnetoresistance in the Fe3O4-based heterostructures is considered to be caused by a shift of the Fe3O4 eg ↑ band near the interface. Enhanced magnetization was observed in Fe3O4/BiFeO3 heterostructures experimentally and further proved by first principle calculations. The enhanced magnetization can be explained by spin moments of the thin BiFeO3 layer substantially reversing into a ferromagnetic arrangement under a strong coupling that is principally induced by electronic orbital reconstruction at the interface.

Key words: reactively sputtered Fe3O4 films, spintronics, magnetoresistance, interface

中图分类号:  (Magnetotransport phenomena; materials for magnetotransport)

  • 75.47.-m
72.25.Mk (Spin transport through interfaces) 81.15.Cd (Deposition by sputtering) 85.75.-d (Magnetoelectronics; spintronics: devices exploiting spin polarized transport or integrated magnetic fields)