Tunnel magnetoresistance in epitaxially grown magnetic tunnel junctions using Heusler alloy electrode and MgO barrier

Tsunegi, S; Sakuraba, Y; Oogane, M; Telling, N D; Shelford, L R; Arenholz, E; van der Laan, G; Hicken, R J; Takanashi, K; Ando, Y

Abstract

Epitaxially grown magnetic tunnel junctions (MTJs) with a stacking structure of Co2MnSi/MgO/CoFe were fabricated. Their tunnel magnetoresistance (TMR) effects were investigated. The TMR ratio and tunnelling conductance characteristics of MTJs were considerably different between those with an MgO barrier prepared using sputtering (SP-MTJ) and those prepared using EB evaporation (EB-MTJ). The EB-MTJ exhibited a very large TMR ratio of 217% at room temperature and 753% at 2 K. The bias voltage dependence of the tunnelling conductance in the parallel magnetic configuration for the EB-MTJ suggests that the observed large TMR ratio at RT results from the coherent tunnelling process through the crystalline MgO barrier. The tunnelling conductance in the anti-parallel magnetic configuration suggests that the large temperature dependence of the TMR ratio results from the inelastic spin–flip tunnelling process.

Citation

Tsunegi, S., Sakuraba, Y., Oogane, M., Telling, N. D., Shelford, L. R., Arenholz, E., …Ando, Y. (2009). Tunnel magnetoresistance in epitaxially grown magnetic tunnel junctions using Heusler alloy electrode and MgO barrier. Journal of Physics D: Applied Physics, 42(19), Article 195004. https://doi.org/10.1088/0022-3727/42/19/195004

• Journal Article Type: Article
• Online Publication Date: Sep 18, 2009
• Publication Date: Oct 7, 2009
• Deposit Date: May 22, 2024
• Journal: Journal of Physics D: Applied Physics
• Print ISSN: 0022-3727
• Electronic ISSN: 1361-6463
• Publisher: IOP Publishing
• Peer Reviewed: Peer Reviewed
• Volume: 42
• Issue: 19
• Article Number: 195004
• DOI: https://doi.org/10.1088/0022-3727/42/19/195004
• Public URL: https://keele-repository.worktribe.com/output/831120
• Publisher URL: https://iopscience.iop.org/article/10.1088/0022-3727/42/19/195004