Relaxation Phenomena of Random Spin System in Itinerant Magnetic Fe_xTiS_2
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Relaxation phenomena of zero-field-cooled isothermal remanent magnetization (IRM) and field-cooled thermoremanent magnetization (TRM) in spin-glass (SG: x = 0.20 and freezing temperature Tg = 41 K) and cluster-glass (CG: x = 1/4, Tg = 53 K) phases of intercalation compound FexTiS2 have been studied using the anomalous Hall effects over the time range 10-1 - 104 s with waiting time tw=180 - 18,000 s at low temperatures T below T/Tg ~ 0.7. After an applied magnetic field is switched off, the time decay of Hall resistivity (or remanent magnetization) follows a power law of the form ρH = At-m within a limited time span, where A is a constant and m an exponent. In both IRM and TRM, the exponent m depends appreciably on the applied magnetic field intensity and temperature, for which we have obtained some universal relationship with a newly introduced quantity of "relative relaxed magnetization". Furthermore, the decay profiles over the wide time range, where the deviations from the power law occur, are analyzed using the existing "domain theory" with some modifications of the theoretical expressions. With the evaluated parameters, discussions are given for the equilibrium relaxation spectra, overlap length, and time-dependent maximum relaxation times that characterize the domain growth and the dynamic properties in this material system.
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(1) Y. Hara, W. X. Gao, H. Negishi, and M. Inoue: Relaxation Behaviors in Cluster-Glass Phase of Itinerant Magnetic FexTiS2 Crystals Studied by Magnetotransport Measurements under Pulsed Magnetic Fields, J. Magn. Magn. Mat. 135 (1994) 311.
(2) Y. Hara, H. Negishi, M. Sasaki, M. Inoue, and V. A. Kulbachinskii: Time Decay of Thermoremanent Magnetization in Cluster-Glass Phase of Intercalation Compound FexTiS2 Studied by Use of Anomalous Hall Effect, J. Magn. Magn. Mat. 145 (1995) 157.
(3) Y. Hara, H. Negishi, M. Sasaki, and M. Inoue: Relaxation of Thermoremanent Magnetization in Spin-Glass Phase of Itinerant Magnetic FexTiS2, J. Magn. Magn. Mat. (1996) (in press).
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