Spin Filtering in Epitaxial Spinel Films with Nanoscale Phase Separation

Peng Li, Chuan Xia, Jun Li, Zhiyong Zhu, Yan Wen, Qiang Zhang, Junwei Zhang, Yong Peng, Husam N. Alshareef, Xixiang Zhang

Research output: Contribution to journalArticle

Abstract

The coexistence of ferromagnetic metallic phase and antiferromagnetic insulating phase in nanoscaled inhomogeneous perovskite oxides accounts for the colossal magnetoresistance. Although the model of spin-polarized electron transport across antiphase boundaries has been commonly employed to account for large magnetoresistance (MR) in ferrites, the magnetic anomalies, the two magnetic phases and enhanced molecular moment, are still unresolved. We observed a sizable MR in epitaxial spinel films (NiCo2O4- δ) that is much larger than that commonly observed in spinel ferrites. Detailed analysis reveals that this MR can be attributed to phase separation, in which the perfect ferrimagnetic metallic phase and ferrimagnetic insulating phase coexist. The magnetic insulating phase plays an important role in spin filtering in these phase separated spinel oxides, leading to a sizable MR effect. A spin filtering model based on Zeeman effect and direct tunneling is developed to account for MR of the phase separated films.

Original languageEnglish (US)
Pages (from-to)5011-5019
Number of pages9
JournalACS nano
Volume11
Issue number5
DOIs
StatePublished - May 23 2017

Keywords

  • Zeeman effect
  • direct tunneling
  • magnetoresistance
  • phase separation
  • spin filter
  • spinel

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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  • Cite this

    Li, P., Xia, C., Li, J., Zhu, Z., Wen, Y., Zhang, Q., Zhang, J., Peng, Y., Alshareef, H. N., & Zhang, X. (2017). Spin Filtering in Epitaxial Spinel Films with Nanoscale Phase Separation. ACS nano, 11(5), 5011-5019. https://doi.org/10.1021/acsnano.7b01743