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Title: Quantitative analysis of anisotropic magnetoresistance in Co{sub 2}MnZ and Co{sub 2}FeZ epitaxial thin films: A facile way to investigate spin-polarization in half-metallic Heusler compounds

Abstract

Anisotropic magnetoresistance (AMR) effect has been systematically investigated in various Heusler compounds Co{sub 2}MnZ and Co{sub 2}FeZ (Z = Al, Si, Ge, and Ga) epitaxial films and quantitatively summarized against the total valence electron number N{sub V}. It was found that the sign of AMR ratio is negative when N{sub V} is between 28.2 and 30.3, and turns positive when N{sub V} becomes below 28.2 and above 30.3, indicating that the Fermi level (E{sub F}) overlaps with the valence or conduction band edges of half-metallic gap at N{sub V} ∼ 28.2 or 30.3, respectively. We also find out that the magnitude of negative AMR ratio gradually increases with shifting of E{sub F} away from the gap edges, and there is a clear positive correlation between the magnitude of negative AMR ratio and magnetoresistive output of the giant magnetoresistive devices using the Heusler compounds. This indicates that AMR can be used as a facile way to optimize a composition of half-metallic Heusler compounds having a high spin-polarization at room temperature.

Authors:
; ; ; ; ;  [1];  [2]
  1. National Institute for Materials Science (NIMS), Sengen 1-2-1, Tsukuba, Ibaraki 305-0047 (Japan)
  2. Graduate School of Engineering, Shizuoka University, Hamamatsu 432-8561 (Japan)
Publication Date:
OSTI Identifier:
22267729
Resource Type:
Journal Article
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 104; Journal Issue: 17; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0003-6951
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANISOTROPY; ELECTRONS; EPITAXY; FERMI LEVEL; MAGNETORESISTANCE; SPIN ORIENTATION; TEMPERATURE RANGE 0273-0400 K; THIN FILMS; VALENCE

Citation Formats

Sakuraba, Y., E-mail: SAKURABA.Yuya@nims.go.jp, Hirayama, Y., Furubayashi, T., Sukegawa, H., Li, S., Takahashi, Y. K., Hono, K., and Kokado, S. Quantitative analysis of anisotropic magnetoresistance in Co{sub 2}MnZ and Co{sub 2}FeZ epitaxial thin films: A facile way to investigate spin-polarization in half-metallic Heusler compounds. United States: N. p., 2014. Web. doi:10.1063/1.4874851.
Sakuraba, Y., E-mail: SAKURABA.Yuya@nims.go.jp, Hirayama, Y., Furubayashi, T., Sukegawa, H., Li, S., Takahashi, Y. K., Hono, K., & Kokado, S. Quantitative analysis of anisotropic magnetoresistance in Co{sub 2}MnZ and Co{sub 2}FeZ epitaxial thin films: A facile way to investigate spin-polarization in half-metallic Heusler compounds. United States. https://doi.org/10.1063/1.4874851
Sakuraba, Y., E-mail: SAKURABA.Yuya@nims.go.jp, Hirayama, Y., Furubayashi, T., Sukegawa, H., Li, S., Takahashi, Y. K., Hono, K., and Kokado, S. 2014. "Quantitative analysis of anisotropic magnetoresistance in Co{sub 2}MnZ and Co{sub 2}FeZ epitaxial thin films: A facile way to investigate spin-polarization in half-metallic Heusler compounds". United States. https://doi.org/10.1063/1.4874851.
@article{osti_22267729,
title = {Quantitative analysis of anisotropic magnetoresistance in Co{sub 2}MnZ and Co{sub 2}FeZ epitaxial thin films: A facile way to investigate spin-polarization in half-metallic Heusler compounds},
author = {Sakuraba, Y., E-mail: SAKURABA.Yuya@nims.go.jp and Hirayama, Y. and Furubayashi, T. and Sukegawa, H. and Li, S. and Takahashi, Y. K. and Hono, K. and Kokado, S.},
abstractNote = {Anisotropic magnetoresistance (AMR) effect has been systematically investigated in various Heusler compounds Co{sub 2}MnZ and Co{sub 2}FeZ (Z = Al, Si, Ge, and Ga) epitaxial films and quantitatively summarized against the total valence electron number N{sub V}. It was found that the sign of AMR ratio is negative when N{sub V} is between 28.2 and 30.3, and turns positive when N{sub V} becomes below 28.2 and above 30.3, indicating that the Fermi level (E{sub F}) overlaps with the valence or conduction band edges of half-metallic gap at N{sub V} ∼ 28.2 or 30.3, respectively. We also find out that the magnitude of negative AMR ratio gradually increases with shifting of E{sub F} away from the gap edges, and there is a clear positive correlation between the magnitude of negative AMR ratio and magnetoresistive output of the giant magnetoresistive devices using the Heusler compounds. This indicates that AMR can be used as a facile way to optimize a composition of half-metallic Heusler compounds having a high spin-polarization at room temperature.},
doi = {10.1063/1.4874851},
url = {https://www.osti.gov/biblio/22267729}, journal = {Applied Physics Letters},
issn = {0003-6951},
number = 17,
volume = 104,
place = {United States},
year = {Mon Apr 28 00:00:00 EDT 2014},
month = {Mon Apr 28 00:00:00 EDT 2014}
}