Effect of disorder on spin-transfer torque in magnetic tunnel junctions

Y. H. Tang; Nicholas Kioussis; Alan Kalitsov; Roberto Car

doi:10.1063/1.3565396

Effect of disorder on spin-transfer torque in magnetic tunnel junctions

Y. H. Tang, Nicholas Kioussis, Alan Kalitsov, Roberto Car

Research output: Contribution to journal › Article › peer-review

4 Scopus citations

Abstract

We have generalized the nonequilibrium Green's functions Keldysh formalism to study the effect of interfacial disorder on the average spin transfer torque, T , in magnetic tunnel junctions (MTJs). We find a sinusoidal angular behavior of the average T as in ideal MTJs. We demonstrate for the first time that the general expression of the bias behavior of the average T in terms of the interplay of average spin current densities in collinear configurations is valid even in the presence of disorder. This explains the strong enhancement and sign reversal of T in the positive bias region, due to the disorder-induced resonance states at interface which selectively assist the transmission of right-coming electrons.

Original language	English (US)
Article number	07C920
Journal	Journal of Applied Physics
Volume	109
Issue number	7
DOIs	https://doi.org/10.1063/1.3565396
State	Published - Apr 1 2011

All Science Journal Classification (ASJC) codes

General Physics and Astronomy

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10.1063/1.3565396

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title = "Effect of disorder on spin-transfer torque in magnetic tunnel junctions",

abstract = "We have generalized the nonequilibrium Green's functions Keldysh formalism to study the effect of interfacial disorder on the average spin transfer torque, T , in magnetic tunnel junctions (MTJs). We find a sinusoidal angular behavior of the average T as in ideal MTJs. We demonstrate for the first time that the general expression of the bias behavior of the average T in terms of the interplay of average spin current densities in collinear configurations is valid even in the presence of disorder. This explains the strong enhancement and sign reversal of T in the positive bias region, due to the disorder-induced resonance states at interface which selectively assist the transmission of right-coming electrons.",

author = "Tang, {Y. H.} and Nicholas Kioussis and Alan Kalitsov and Roberto Car",

note = "Funding Information: We acknowledge support from the National Center for Theoretical Sciences (South), Taiwan. The work at California State University, Northridge was supported by NSF-PREM Grant No. and at Princeton University by DOE Grant No. .",

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T1 - Effect of disorder on spin-transfer torque in magnetic tunnel junctions

AU - Tang, Y. H.

AU - Kioussis, Nicholas

AU - Kalitsov, Alan

AU - Car, Roberto

N1 - Funding Information: We acknowledge support from the National Center for Theoretical Sciences (South), Taiwan. The work at California State University, Northridge was supported by NSF-PREM Grant No. and at Princeton University by DOE Grant No. .

PY - 2011/4/1

Y1 - 2011/4/1

N2 - We have generalized the nonequilibrium Green's functions Keldysh formalism to study the effect of interfacial disorder on the average spin transfer torque, T , in magnetic tunnel junctions (MTJs). We find a sinusoidal angular behavior of the average T as in ideal MTJs. We demonstrate for the first time that the general expression of the bias behavior of the average T in terms of the interplay of average spin current densities in collinear configurations is valid even in the presence of disorder. This explains the strong enhancement and sign reversal of T in the positive bias region, due to the disorder-induced resonance states at interface which selectively assist the transmission of right-coming electrons.

AB - We have generalized the nonequilibrium Green's functions Keldysh formalism to study the effect of interfacial disorder on the average spin transfer torque, T , in magnetic tunnel junctions (MTJs). We find a sinusoidal angular behavior of the average T as in ideal MTJs. We demonstrate for the first time that the general expression of the bias behavior of the average T in terms of the interplay of average spin current densities in collinear configurations is valid even in the presence of disorder. This explains the strong enhancement and sign reversal of T in the positive bias region, due to the disorder-induced resonance states at interface which selectively assist the transmission of right-coming electrons.

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Effect of disorder on spin-transfer torque in magnetic tunnel junctions

Abstract

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