“School of Nano-Sciences”
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| Paper IPM / Nano-Sciences / 8142 |
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| Abstract: | |
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Theoretical studies on spin-dependent transport in magnetic tunnel heterostructures consisting
of two diluted magnetic semiconductors (DMS) separated by a nonmagnetic semiconductor (NMS)
barrier, are carried in the limit of coherent regime by including the effect of angular dependence of the
magnetizations in DMS. Based on parabolic valence band effective mass approximation and spontaneous
magnetization of DMS electrodes, we obtain an analytical expression of angular dependence of transmission
for DMS/NMS/DMS junctions. We also examine the dependence of spin polarization and tunneling
magnetoresistance (TMR) on barrier thickness, temperature, applied voltage and the relative angle between
the magnetizations of two DMS layers in GaMnAs/GaAs/GaMnAs heterostructures. We discuss the
theoretical interpretation of this variation. Our results show that TMR of more than 65zero temperature, when one GaAs monolayer is used as a tunnel barrier. It is also shown that the TMR
decreases rapidly with increasing barrier width and applied voltage; however at high voltages and low
thicknesses, the TMR first increases and then decreases. Our calculations explain the main features of the
recent experimental observations and the application of the predicted results may prove useful in designing
nano spin-valve devices.
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