High spin polarization in epitaxial Fe4N thin films using Cr and Ag as buffer layers

Hongshi Li, Xuan Li, Dongrin Kim, Gejian Zhao, Delin Zhang, Zhitao Diao, Tingyong Chen, Jian Ping Wang

Research output: Contribution to journalArticle

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Abstract

Fe4N thin films with (001) texture were prepared by reactive sputtering on MgO substrates, utilizing either a Cr or Ag buffer layer to facilitate the epitaxial growth. X-ray diffraction, atomic force microscopy, and vibrating sample magnetometry measurements show that the Fe4N thin film grown on the Ag buffer layer is superior to that grown on the Cr buffer layer. The point contact Andreev reflection measurement was then conducted, and the spin polarizations were determined to be 61.1% and 81.3% for Fe4N thin films with Cr and Ag buffer layers, respectively. The 81.3% spin polarization is significantly higher than the ratio reported previously for Fe4N and is comparable with that of state-of-the-art Heusler alloys. This result is in agreement with the theoretical prediction on the discrepancy between the two differently defined spin polarizations for Fe4N. Moreover, our study indicates that an optimized growth process for Fe4N thin films is crucial for achieving a high spin polarization and that true half-metallicity could potentially be realized with Fe4N. The high spin polarization of Fe4N combined with its low fabrication temperature and simple composition makes Fe4N a competitive candidate to be a half-metallic ferromagnet in spintronic devices.

Original languageEnglish (US)
Article number162407
JournalApplied Physics Letters
Volume112
Issue number16
DOIs
StatePublished - Apr 16 2018

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buffers
polarization
thin films
metallicity
magnetic measurement
textures
sputtering
atomic force microscopy
fabrication
predictions
diffraction
x rays
temperature

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

Cite this

Li, H., Li, X., Kim, D., Zhao, G., Zhang, D., Diao, Z., ... Wang, J. P. (2018). High spin polarization in epitaxial Fe4N thin films using Cr and Ag as buffer layers. Applied Physics Letters, 112(16), [162407]. https://doi.org/10.1063/1.5023698

High spin polarization in epitaxial Fe4N thin films using Cr and Ag as buffer layers. / Li, Hongshi; Li, Xuan; Kim, Dongrin; Zhao, Gejian; Zhang, Delin; Diao, Zhitao; Chen, Tingyong; Wang, Jian Ping.

In: Applied Physics Letters, Vol. 112, No. 16, 162407, 16.04.2018.

Research output: Contribution to journalArticle

Li, H, Li, X, Kim, D, Zhao, G, Zhang, D, Diao, Z, Chen, T & Wang, JP 2018, 'High spin polarization in epitaxial Fe4N thin films using Cr and Ag as buffer layers', Applied Physics Letters, vol. 112, no. 16, 162407. https://doi.org/10.1063/1.5023698
Li, Hongshi ; Li, Xuan ; Kim, Dongrin ; Zhao, Gejian ; Zhang, Delin ; Diao, Zhitao ; Chen, Tingyong ; Wang, Jian Ping. / High spin polarization in epitaxial Fe4N thin films using Cr and Ag as buffer layers. In: Applied Physics Letters. 2018 ; Vol. 112, No. 16.
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