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Description:

We demonstrate tunnel magnetoresistance (TMR) ratios of up to 631% at room temperature (RT) using CoFe/MgO/CoFe(001) epitaxial magnetic tunnel junctions (MTJs). The TMR ratio increased up to 1143% at 10 K. The large TMR ratios resulted from the fine-tuning of the atomic-scale structures of the MTJs, such as crystallographic orientations and MgO interface oxidation, which are expected to enhance the well-known Δ1 coherent tunneling transport. Interestingly, the TMR oscillation effect, which is not covered by the standard coherent tunneling theory, also became significant. A 0.32-nm period TMR oscillation with increasing MgO thickness dominates the transport in a wide range of MgO thicknesses; the peak-to-valley difference of the TMR oscillation exceeds 140% at RT, which is attributed to the appearance of large oscillatory components in the resistance area product.

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• Creative Commons BY Attribution 4.0 International
  

  ©2023 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http:// creativecommons.org/licenses/by/4.0/).

Keyword: magnetic tunnel junctions, tunnel magnetoresistance, TMR, spintronics, MgO, epitaxial growth

Date published: 2023-03-13

Publisher: AIP Publishing

Journal:

• APPLIED PHYSICS LETTERS (ISSN: 00036951) vol. 122 issue. 11 p. 112404-112404

Funding:

• JSPS 16H06332 (JSPS KAKENHI)
• JSPS 21H01750 (JSPS KAKENHI)
• JSPS 21H01397 (JSPS KAKENHI)
• Cabinet Office, Government of Japan (ImPACT Program of the Council for Science, Technology and Innovation)
• NEDO JPNP16007 (NEDO)

Manuscript type: Publisher's version (Version of record)

MDR DOI:

First published URL: https://doi.org/10.1063/5.0145873

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Updated at: 2024-01-05 22:12:02 +0900

Published on MDR: 2024-01-16 19:52:29 +0900