K Shiiki 2011 J. Phys.: Conf. Ser. 303 012101 doi:10.1088/1742-6596/303/1/012101
K Shiiki
Show affiliationsThe conductivity asymmetry of junctions with insulating MgO barriers embedded between ferromagnetic Fe electrodes has been investigated by the first principles calculation program of Atomistix ToolKit 2008. The conductivity in up-spin electron is larger than that in down-spin electron for the ideal structure. It leads to the large TMR ratio. The defect of O or Fe atoms hardly varies the conductivity in both up and down-spin electrons. The defect of Mg atoms increases the conductivity in down-spin electron, although the up-spin conductivity does not change very much. So the defect of Mg decreases the TMR ratio. The defect of Mg near the interface especially shows this degradation. The derivative conductivity dI/dV vs. V characteristics are asymmetric for the polarity of the bias voltage V according to the location of the atom defect. The quality of the junction in devices can be evaluated by the asymmetry.
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
71.15.-m Methods of electronic structure calculations
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)
75.47.-m Magnetotransport phenomena; materials for magnetotransport
Condensed matter: electrical, magnetic and optical
Issue 1 (2011)
K Shiiki 2011 J. Phys.: Conf. Ser. 303 012101
Arno Onken and Klaus Obermayer 2009 J. Phys.: Conf. Ser. 197 012019
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