Spin dynamics under local gauge fields in chiral spin-orbit coupling systems

Journal Article · Tue Feb 15 00:00:00 EST 2011 · Annals of Physics (New York)

DOI:https://doi.org/10.1016/j.aop.2010.11.014· OSTI ID:21579844

Jalil, M B.A. ^[1]; Fujita, T ^[1]; Liu, X J ^[2]

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1. Information Storage Materials Laboratory, Electrical and Computer Engineering Department, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore)
2. Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore)

Research Highlights: > We derive a modified LLG equation in magnetic systems with spin-orbit coupling (SOC). > Our results are applied to magnetic multilayers, and DMS and magnetic Rashba systems. > SOC mediated magnetization switching is predicted in rare earth metals (large SOC). > The magnetization trajectory and frequency can be modulated by applied voltage. > This facilitates potential application as tunable microwave oscillators. - Abstract: We present a theoretical description of local spin dynamics in magnetic systems with a chiral spin texture and finite spin-orbit coupling (SOC). Spin precession about the relativistic effective magnetic field in a SOC system gives rise to a non-Abelian SU(2) gauge field reminiscent of the Yang-Mills field. In addition, the adiabatic relaxation of electron spin along the local spin yields an U(1) x U(1) topological gauge (Berry) field. We derive the corresponding equation of motion i.e. modified Landau-Lifshitz-Gilbert (LLG) equation, for the local spin under the influence of these effects. Focusing on the SU(2) gauge, we obtain the spin torque magnitude, and the amplitude and frequency of spin oscillations in this system. Our theoretical estimates indicate significant spin torque and oscillations in systems with large spin-orbit coupling, which may be utilized in technological applications such as current-induced magnetization-switching and tunable microwave oscillators.

• OSTI ID: 21579844
• Journal Information: Annals of Physics (New York), Vol. 326, Issue 2; Other Information: DOI: 10.1016/j.aop.2010.11.014; PII: S0003-4916(10)00203-4; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0003-4916
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
AMPLITUDES
CHIRALITY
ELECTRIC POTENTIAL
EQUATIONS OF MOTION
L-S COUPLING
MAGNETIC FIELDS
MAGNETIZATION
MICROWAVE RADIATION
OSCILLATIONS
POTENTIALS
RARE EARTHS
RELATIVISTIC RANGE
RELAXATION
SPIN
TOPOLOGY
TRAJECTORIES
YANG-MILLS THEORY
ANGULAR MOMENTUM
COUPLING
DIFFERENTIAL EQUATIONS
ELECTROMAGNETIC RADIATION
ELEMENTS
ENERGY RANGE
EQUATIONS
INTERMEDIATE COUPLING
MATHEMATICS
METALS
PARTIAL DIFFERENTIAL EQUATIONS
PARTICLE PROPERTIES
RADIATIONS