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

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.
Authors:
; ; ; ;  [1] ;  [2] ; ;  [3] ; ; ;  [4]
  1. Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan)
  2. Photon Factory, IMSS, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801 (Japan)
  3. Research Institute of Electrical Communication, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577 (Japan)
  4. Division of Electronics for Informatics, Hokkaido University, Sapporo 060-0814 (Japan)
Publication Date:
OSTI Identifier:
22410244
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 20; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
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