The effects of a magnetic barrier and a nonmagnetic spacer in tunnel structures

Abstract

The spin-polarized transport is investigated in a new type of magnetic tunnel junction which consists of two ferromagnetic electrodes separated by a magnetic barrier and a nonmagnetic metallic spacer. Based on the transfer matrix method and the nearly-free-electron-approximation the dependence of the tunnel magnetoresistance (TMR) and electron-spin polarization on the nonmagnetic layer thickness and the applied bias voltage are studied theoretically. The TMR and spin polarization show an oscillatory behavior as a function of the spacer thickness and the bias voltage. The oscillations originate from the quantum well states in the spacer, while the existence of the magnetic barrier gives rise to a strong spin polarization and high values of the TMR. Our results may be useful for the development of spin electronic devices based on coherent transport.

arXiv comment15 pages, 5 figures

References in corpus (3)

• Large magnetoresistance using hybrid spin filter devices
• Spin-filter magnetoresistance in magnetic barrier junctions
• Tunnel magnetoresistance in double spin filter junctions

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• Quantum theory of tunneling magnetoresistance in GaMnAs/GaAs/GaMnAs heterostructures
• Spin-dependent resonant tunneling in ZnSe/ZnMnSe heterostructures
• Selective spin transport through a quantum heterostructure: Transfer matrix method