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Nonequilibrium Dynamical Phase Transition of a Three-Dimensional Kinetic Heisenberg Spin System |
| SHAO Yuan-Zhi1; J. K. L. Lai2;C. H. Shek2;LIN Guang-Min1;LAN Tu1 |
| 1Department of Physics, Zhongshan University, Guangzhou 510275
2Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong |
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| Cite this article: |
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SHAO Yuan-Zhi, J. K. L. Lai, C. H. Shek et al 2002 Chin. Phys. Lett. 19 1344-1346 |
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Abstract We systematically investigate the dynamical response of a three-dimensional kinetic isotropic Heisenberg spin system (HSS) to an external driving field by Monte Carlo numerical simulation. The dynamical response of isotropic HSS differs obviously from those of the anisotropic Ising spin system in which no real stable ordered state and relevant dynamical phase transition were observed in the kinetic HSS. There is a threshold time after which the magnetization m(t) in the HSS driven by a symmetrical external field always tends asymptotically to a disorder state regardless of the initial state of the system. The threshold time depends on the reduced temperature T/TC of the investigated spin system, amplitude H0 and frequency of the external field, i.e., τ = C.ωα.H-β0.(T/TC)-γ. C is a constant equal to 0.0302 for a three-dimensional lattice and exponents α = 1.18±0.01, β = 1.81±0.01 and γ = 1.68±0.01.
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| Keywords:
75.10.Hk
05.10.Ln
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Published: 01 September 2002
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