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Nonequilibrium process of magnetization switching influenced by thermal spin fluctuations
Author(s) -
Choi B. C.,
Hong Y. K.,
Rudge J.,
Girgis E.,
Kolthammer J.,
Donohoe G. W.
Publication year - 2007
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200777167
Subject(s) - magnetization , magnetization dynamics , spins , condensed matter physics , non equilibrium thermodynamics , ferromagnetism , switching time , kerr effect , field (mathematics) , physics , magnetic domain , magnetic field , spin (aerodynamics) , quantum mechanics , optoelectronics , mathematics , nonlinear system , pure mathematics , thermodynamics
We present a systematic study of the dynamic behavior of nonequilibrium magnetization configurations with time‐resolved scanning Kerr microscope and micromagnetic modeling. The magnetization switching dynamics enters a fully dynamic regime when the external field conditions are changed much faster than the magnetization in the elements is able to respond. We observe that the dynamic pathway develops a complexity not seen in quasi‐static reversal, but still retains a high level of order with well‐developed dynamic domain patterns formed in response to sub‐nanosecond transitions of the external applied magnetic field pulse. An increasing complexity in the spatial structure of the evolution is found to accompany the increasing switching speed, when a ferromagnetic element is driven by progressively faster reversing fields applied anti‐parallel to the initial magnetization direction. The sensitive dependence of the nonequilibrium magnetization configurations on switching speed can be understood in terms of a dynamic exchange interaction of thermally excited spins; the coherent modulation of the spins is strongly dependent on the rise time of switching magnetic field pulses. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)