Ranulfo Allen, John Baglin, et al.
J. Photopolym. Sci. Tech.
Bardeen's transfer-Hamiltonian method is applied to magnetic tunnel junctions having a general degree of atomic disorder. The results reveal a close relationship between magnetoconduction and voltage-driven pseudotorque, and also provide a means of predicting the thickness dependence of tunnel-polarization factors. Among the results: (i) The torque generally varies with moment direction as sin θ at constant applied voltage, (ii) Whenever polarization factors are well defined, the voltage-driven torque on each moment is uniquely proportional to the polarization factor of the other magnet, (iii) At finite applied voltage, this relation implies significant voltage-asymmetry in the torque. For one sign of voltage the torque remains substantial even if the magnetoconductance is greatly diminished, (iv) A broadly defined junction model, called ideal middle, allows for atomic disorder within the magnets and F/I interface regions. In this model, the spin-(σ) dependence of a basis-state weighting factor proportional to the sum over general state index p of (∫∫dydzΨp,σ) 2 evaluated within the (e.g., vacuum) barrier generalizes the local state density in previous theories of the tunnel-polarization factor, (v) For small applied voltage, tunnel-polarization factors remain legitimate up to first order in the inverse thickness of the ideal middle. An algebraic formula describes the first-order corrections to polarization factors in terms of newly defined lateral autocorrellation scales. ©2005 The American Physical Society.
Ranulfo Allen, John Baglin, et al.
J. Photopolym. Sci. Tech.
Frank R. Libsch, Takatoshi Tsujimura
Active Matrix Liquid Crystal Displays Technology and Applications 1997
J.H. Stathis, R. Bolam, et al.
INFOS 2005
Heinz Schmid, Hans Biebuyck, et al.
Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures