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Probing the electronic states of high-TMR off-stoichiometric Co2MnSI thin films by hard x-ray photoelectron spectroscopy.
- Source :
-
Physical Review B: Condensed Matter & Materials Physics . Mar2014, Vol. 89 Issue 12, p125116-1-125116-10. 10p. - Publication Year :
- 2014
-
Abstract
- The tunnel magnetoresistance ratio (TMR) of fully epitaxial magnetic tunnel junctions with an off- stoichiometric Co2MnSi Heusler alloy has been shown to exhibit a systematic dependence on Mn content, reaching 1135% at 4.2 K for Co2Mn1.29Si. In this paper, we explain the behaviorof the observed TMR ratio using ab initio calculations and hard x-ray photoelectron spectroscopy (HAXPES). For the Mn-deficient samples, we show that the the drop of the TMR is caused by Co antisite atoms, which impose extra states into the minority-spin band gap. On the other hand, Mn-excess composition shows nearly half-metallic behavior. This result can be intuitively understood since both Co2MnSi and Mn2CoSi are theoretically predicted to be half-metallic ferromagnets. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 10980121
- Volume :
- 89
- Issue :
- 12
- Database :
- Academic Search Index
- Journal :
- Physical Review B: Condensed Matter & Materials Physics
- Publication Type :
- Academic Journal
- Accession number :
- 95934068
- Full Text :
- https://doi.org/10.1103/PhysRevB.89.125116