Dynamics of current induced magnetic superstructures in exchange-spring devices
Department of Physics, University of Gothenburg, SE-412 96 Gothenburg, Sweden Theoretische Physik III, Ruhr-Universität Bochum, D-44801 Bochum, Germany
Department of Physics, University of Gothenburg, SE-412 96 Gothenburg, Sweden
Department of Physics, University of Gothenburg, SE-412 96 Gothenburg, Sweden SUPA, Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, Scotland, UK
Department of Physics, Division of Quantum Phases and Devices, Konkuk University, Seoul 143-701, Republic of Korea
Received February 6, 2012
Thermoelectric manipulation of the magnetization of a magnetic layered stack in which a low-Curie temperature
magnet is sandwiched between two strong magnets (exchange spring device) is considered. Controllable Joule heating produced by a current flowing in the plane of the magnetic stack (CIP configuration) induces a spatial magnetic and thermal structure along the current flow — a magnetothermal-electric domain (soliton). We show that such a structure can experience oscillatory in time dynamics if the magnetic stack is incorporated into an electric circuit in series with an inductor. The excitation of these magnetothermionic oscillations follow
the scenario either of “soft” of “hard” instability: in the latter case oscillations arise if the initial perturbation is large enough. The frequency of the temporal oscillations is of the order of 105–107 s–1 for current densities j ~ 106–107 A/cm2.
PACS: 75.45.+j Macroscopic quantum phenomena in magnetic systems; PACS: 75.70.–i Magnetic properties of thin films, surfaces, and interfaces.