Theory of tunneling magnetoresistance of an epitaxial Fe/MgO/Fe(001) junction
Calculation of the tunneling magnetoresistance (TMR) of an epitaxial Fe/MgO/Fe(001) junction is reported. The conductances of the junction in its ferromagnetic and antiferromagnetic configurations are determined without any approximations from the real-space Kubo formula using tight-binding bands fitted to an ab initio band structure of iron and MgO. The calculated optimistic TMR ratio is in excess of 1000% for an MgO barrier of {approximately}20 atomic planes and the spin polarization of the tunneling current is positive for all MgO thicknesses. It is also found that spin-dependent tunneling in an Fe/MgO/Fe(001) junction is not entirely determined by states at the {Gamma} point (k{sub {parallel}}=0) even for MgO thicknesses as large as {approximately}20 atomic planes. All these results are explained qualitatively in terms of the Fe majority- and minority-spin surface spectral densities and the complex MgO Fermi surface.
- Sponsoring Organization:
- (US)
- OSTI ID:
- 40203461
- Journal Information:
- Physical Review B, Vol. 63, Issue 22; Other Information: DOI: 10.1103/PhysRevB.63.220403; Othernumber: PRBMDO000063000022220403000001; R18118PRB; PBD: 1 Jun 2001; ISSN 0163-1829
- Publisher:
- The American Physical Society
- Country of Publication:
- United States
- Language:
- English
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