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Effects of FM/NM Interfaces on Spin Accumulation in Free Layer of Pseudo-Spin-Valve Structure

Published online by Cambridge University Press:  21 March 2011

Jiuning Hu ,
Min Ren ,
Lei Zhang ,
Ning Deng ,
Hao Dong  and
Peiyi Chen
Jiuning Hu
Affiliation:
Institute of Microelectronics, Tsinghua University, Beijing, 100084, China, People's Republic of
Min Ren
Affiliation:
Institute of Microelectronics, Tsinghua University, Beijing, 100084, China, People's Republic of
Lei Zhang
Affiliation:
Institute of Microelectronics, Tsinghua University, Beijing, 100084, China, People's Republic of
Ning Deng
Affiliation:
Institute of Microelectronics, Tsinghua University, Beijing, 100084, China, People's Republic of
Hao Dong
Affiliation:
Institute of Microelectronics, Tsinghua University, Beijing, 100084, China, People's Republic of
Peiyi Chen
Affiliation:
Institute of Microelectronics, Tsinghua University, Beijing, 100084, China, People's Republic of
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Abstract

The ferromagnetic/nonmagnetic (FM/NM) interfacial effects on the spin accumulation in the free layer were studied in a pseudo-spin-valve structure (PSVs) consisting of two FM layers separated by a NM spacer layer. We developed a spin current model for the current-induced magnetic switching (CIMS) effect based on the spin diffusion equations and appropriate boundary conditions, and derived a new formula for the spin-dependent electrochemical potentials that are related to the spin-dependent density of states. The results indicate that the spin accumulation in the free layer mainly depends on the interfacial spin asymmetry coefficient Ξ?which originates from the spin-dependent interfacial conductance. In the parallel (anti-parallel) configuration of the magnetization direction for the free and fixed layer, the positive (negative) electron current (electrons from the free layer to the fixed layer and vice versa) drives the spin current polarization factor at the interface between the top electrode and the free layer to vary from Ξ? (-Ξ?) to 0, while at the interface between the free layer and the spacer layer the spin current polarization factor vary from Ξ? (0) to Ξ?/2, which means the total spin current polarization factor in the free layer varies from 0 (Ξ?) to Ξ?/2. These results show that the anti-parallel configuration has a less critical switching current than that of the parallel configuration. Thus, we can design PSVs with symmetrical critical current based on the model.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 998: Symposium J – Nanoscale Magnetics and Device Applications , 2007 , 998-J02-03
Copyright
Copyright © Materials Research Society 2007

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References

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