Electronic and magnetic properties of off-stoichiometric Co{sub 2}Mn{sub β}Si/MgO interfaces studied by x-ray magnetic circular dichroism

Journal Article · Thu May 28 00:00:00 EDT 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4921538· OSTI ID:22410244

Singh, V. R.; Verma, V. K.; Ishigami, K.; Shibata, G.; Koide, T. ^[1]; Miura, Y.; Shirai, M. ^[2]; Ishikawa, T.; Li, G. -F.; Yamamoto, M. ^[3]

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1. Photon Factory, IMSS, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801 (Japan)
2. Research Institute of Electrical Communication, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577 (Japan)
3. Division of Electronics for Informatics, Hokkaido University, Sapporo 060-0814 (Japan)

We have studied the electronic and magnetic states of Co and Mn atoms at the interface of the Co{sub 2}Mn{sub β}Si (CMS)/MgO (β = 0.69, 0.99, 1.15, and 1.29) magnetic tunnel junction (MTJ) by means of x-ray magnetic circular dichroism. In particular, the Mn composition (β) dependences of the Mn and Co magnetic moments were investigated. The experimental spin magnetic moments of Mn, m{sub spin}(Mn), derived from x-ray magnetic circular dichroism weakly decreased with increasing Mn composition β in going from Mn-deficient to Mn-rich CMS films. This behavior was explained by first-principles calculations based on the antisite-based site-specific formula unit (SSFU) composition model, which assumes the formation of only antisite defect, not vacancies, to accommodate off-stoichiometry. Furthermore, the experimental spin magnetic moments of Co, m{sub spin}(Co), also weakly decreased with increasing Mn composition. This behavior was consistently explained by the antisite-based SSFU model, in particular, by the decrease in the concentration of Co{sub Mn} antisites detrimental to the half-metallicity of CMS with increasing β. This finding is consistent with the higher tunnel magnetoresistance ratios which have been observed for CMS/MgO/CMS MTJs with Mn-rich CMS electrodes.

• OSTI ID: 22410244
• Journal Information: Journal of Applied Physics, Vol. 117, Issue 20; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CONCENTRATION RATIO
COPPER COMPOUNDS
FILMS
INTERFACES
MAGNESIUM OXIDES
MAGNETIC CIRCULAR DICHROISM
MAGNETIC MOMENTS
MAGNETIC PROPERTIES
MAGNETORESISTANCE
MANGANESE SILICIDES
METALLICITY
SPIN
STOICHIOMETRY
TUNNEL EFFECT
VACANCIES
X RADIATION