Hai-Feng Mu, Zhen-Gang Zhu, Qing-Rong Zheng, Biao Jin, Zheng-Chuan Wang, Gang Su ∗

Department of Physics, The Graduate School of the Chinese Academy of Sciences, PO Box 3908, Beijing 100039, PR China

Received 11 January 2004; accepted 27 January 2004

Communicated by V.M. Agranovich

Abstract

    A recent elegant experimental realization [S. Yuasa et al., Science 297 (2002) 234] of the spin-polarized resonant tunneling in magnetic tunnel junctions is interpreted in terms of a two-band model. It is shown that the tunnel magnetoresistance (TMR) decays oscillatorily with the thickness of the normal metal (NM) layer, being fairly in agreement with the experimental observation. The tunnel conductance is found to decay with slight oscillations with the increase of the NM layer thickness, which is also well consistent with the experiment. In addition, when the magnetizations of both ferromagnet electrodes are not collinearly aligned, TMR is found to exhibit sharp resonant peaks at some particular thickness of the NM layer. The peaked TMR obeys nicely a Gaussian distribution against the relative orientation of the magnetizations.  2004 Elsevier B.V. All rights reserved.

PACS: 75.70.-i; 75.70.Pa; 73.40.Gk