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Search Publications by: Mark D. Stiles (Fed)

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Displaying 226 - 250 of 383

Spin Transfer Torque for Continuously Variable Magnetization

February 21, 2006
Author(s)
J Xiao, A Zangwill, Mark D. Stiles
We report quantum and semi-classical calculations of spin current and spin-transfer torque in a free-electron Stoner model for systems where the magnetization varies continuously in one dimension. Analytic results are obtained for an infinite spin spiral

Spin Transport for Spin Diffusion Lengths Comparable to Mean Free Paths

December 15, 2005
Author(s)
David R. Penn, Mark D. Stiles
In perpendicular-transport structures with magnetic and non-magnetic layers, there is a resistance associated with changes in the value of current polarization throughout the structure. Starting from a Boltzmann equation Valet and Fert derived macroscopic

Macrospin Models of Spin Transfer Dynamics

July 1, 2005
Author(s)
J Xiao, A Zangwill, Mark D. Stiles
The current-induced magnetization dynamics of a spin valve are studied using a macrospin (single-domain) approximation and numerical solutions of a generalized Landau-Lifshitz-Gilbert equation. For the purpose of quantitative comparison to experiment [S. I

Current-induced switching in a single exchange-biased ferromagnetic layer

May 15, 2005
Author(s)
Tingyong Chen, Yi Ji, C Chien, Mark D. Stiles
We demonstrate current-induced switching effects in a single exchanged-biased ferromagnetic layer. A nanodomain can be switched within the ferromagnetic layer by a spin polarized current injected through a point contact. The high resistance of the

Magnetic normal modes of nano-elements

May 15, 2005
Author(s)
Robert McMichael, Mark D. Stiles
Micromagnetic calculations are used to determine the eigenfrequencies and precession patterns of some of the lowest-frequency magnetic normal modes of submicron patterned elements. For a Permalloy-like ellipse, 350 nm ¿ 160 nm ¿ 5 nm thick in zero field

Magnetic Normal Modes of Nanoelements

May 1, 2005
Author(s)
Robert D. McMichael, Mark D. Stiles
Micromagnetic calculations are used to determine the eigenfrequencies and precession patterns of some of the lowest-frequency magnetic normal modes of submicron patterned elements. For a Permalloy-like ellipse, 350 nm 160 nm 5 nm thick in zero field, the

Artifacts That Mimic Ballistic Magnetoresistance

February 1, 2005
Author(s)
William F. Egelhoff Jr., L Gan, H Ettedgui, Y Kadmon, Cedric J. Powell, P J. Chen, Alexander J. Shapiro, Robert McMichael, J Mallett, Thomas P. Moffat, Mark D. Stiles, Erik B. Svedberg
We have investigated the circumstances underlying recent reports of very large values of ballistic magntoresistance (BMR) in nanocontacts between magnetic wires. We find that the geometries used are subject to artifacts due to motion of the wires that

Interlayer Exchange Coupling

December 13, 2004
Author(s)
Mark D. Stiles
In magnetic multilayers, in which ferromagnetic layers are separated by non-magnetic spacer layers, the magnetizations are coupled by interactions across the spacer layer. One type of coupling, bilinear exchange coupling, originates from the quantum well

Boltzmann Test of Slonczewski's Theory of Spin Transfer Torque

November 12, 2004
Author(s)
J Xiao, A Zangwill, Mark D. Stiles
We use a matrix Boltzmann equation formalism to test the accuracy of Slonczewski's theory of spin-transfer torque in thin-film heterostructures where a non-magnetic spacer layer separates two non-collinear ferromagnetic layers connected to non-magnetic

Current-driven switching in a single exchange-biased ferromagnetic layer

July 9, 2004
Author(s)
Tingyong Chen, Yi Ji, C Chien, Mark D. Stiles
We demonstrate spin-transfer torque effects in a single exchange-biased ferromagnetic layer. A current through a point contact to the exchange-biased Co layer reverses the magnetization of a nanodomain in the layer hysteretically for low applied magnetic

Artifacts in Ballistic Magnetoresistance Measurements

June 1, 2004
Author(s)
William F. Egelhoff Jr., L Gan, H Ettedgui, Y Kadmon, Cedric J. Powell, P J. Chen, Alexander J. Shapiro, Robert McMichael, J Mallett, Thomas P. Moffat, Mark D. Stiles, Erik B. Svedberg
We have studied the behavior of electrodeposited Ni and Fe nanocontacts in magnetic fields and the changes in resistivity (Δ}R) that occur. Metallic particles suspended in plating solution, created and collected from the electroplating bath of a

Artifacts in Ballistic Magnetoresistance Measurements

June 1, 2004
Author(s)
William F. Egelhoff Jr., L Gan, H Ettendgui, Y Kadmon, Cedric J. Powell, P J. Chen, Alexander J. Shapiro, Robert McMichael, J Mallett, Thomas P. Moffat, Mark D. Stiles
We have carried out an extensive search for credible evidence to support the existence of a ballistic magnetoresistance (BMR) effect in magnetic nanocontacts. We have investigated both thin-film and thin-wire geometries for both mechanically-formed and

Spin Nomenclature for Semiconductors and Magnetic Metals

June 1, 2004
Author(s)
B Jonker, A Hanbicki, Daniel T. Pierce, Mark D. Stiles
The different conventions used in the semiconductor and magnetic metals communities can cause confusion in the context of spin polarization and transport in simple heterostructures. In semiconductors, terminology is based on the orientation of the electron