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Title: High spin polarization in epitaxial Fe 4N thin films using Cr and Ag as buffer layers

Abstract

Fe 4N 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 Fe 4N 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 Fe 4N thin films with Cr and Ag buffer layers, respectively. The 81.3% spin polarization is significantly higher than the ratio reported previously for Fe 4N 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 Fe 4N. Moreover, our study indicates that an optimized growth process for Fe 4N thin films is crucial for achieving a high spin polarization and that true half-metallicity could potentially be realized with Fe 4N. Furthermore the high spin polarization of Fe 4N combined with its low fabrication temperature and simple composition makes Fe 4N a competitive candidate to be a half-metallic ferromagnetmore » in spintronic devices.« less

Authors:
 [1];  [1];  [2];  [2];  [1];  [3]; ORCiD logo [2];  [1]
  1. Univ. of Minnesota, Minneapolis, MN (United States)
  2. Arizona State Univ., Tempe, AZ (United States)
  3. Western Digital Corp., San Jose, CA (United States)
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Spins and Heat in Nanoscale Electronic Systems (SHINES); Univ. of California, Riverside, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
OSTI Identifier:
1503634
Alternate Identifier(s):
OSTI ID: 1433574
Grant/Contract Number:  
SC0012670
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 112; Journal Issue: 16; Journal ID: ISSN 0003-6951
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY

Citation Formats

Li, Hongshi, Li, Xuan, Kim, Dongrin, Zhao, Gejian, Zhang, Delin, Diao, Zhitao, Chen, Tingyong, and Wang, Jian -Ping. High spin polarization in epitaxial Fe4N thin films using Cr and Ag as buffer layers. United States: N. p., 2018. Web. doi: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. United States. https://doi.org/10.1063/1.5023698
Li, Hongshi, Li, Xuan, Kim, Dongrin, Zhao, Gejian, Zhang, Delin, Diao, Zhitao, Chen, Tingyong, and Wang, Jian -Ping. Wed . "High spin polarization in epitaxial Fe4N thin films using Cr and Ag as buffer layers". United States. https://doi.org/10.1063/1.5023698. https://www.osti.gov/servlets/purl/1503634.
@article{osti_1503634,
title = {High spin polarization in epitaxial Fe4N thin films using Cr and Ag as buffer layers},
author = {Li, Hongshi and Li, Xuan and Kim, Dongrin and Zhao, Gejian and Zhang, Delin and Diao, Zhitao and Chen, Tingyong and Wang, Jian -Ping},
abstractNote = {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. Furthermore 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.},
doi = {10.1063/1.5023698},
url = {https://www.osti.gov/biblio/1503634}, journal = {Applied Physics Letters},
issn = {0003-6951},
number = 16,
volume = 112,
place = {United States},
year = {2018},
month = {4}
}

Journal Article:
Free Publicly Available Full Text
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Cited by: 3 works
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Figures / Tables:

FIG. 1 FIG. 1: (a) θ-2 θ XRD scans of the Fe 4N films grown on Cr and Ag buffer layers. (b) Rocking curve measurement of Fe 4N (002) peaks.

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Works referenced in this record:

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    Works referencing / citing this record:

    Strain relaxation in epitaxial γ ′-Fe 4 N ultrathin films
    journal, September 2019


    Effect of interfacial interdiffusion on magnetism in epitaxial Fe 4 N films on LaAlO 3 substrates
    journal, November 2019


      Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.