Spin glasses in low DC fields. II. Magnetic viscosity
C N Guy; C N Guy; Phys. Dept., Imperial Coll., London, UK
Журнал:
Journal of Physics F: Metal Physics
Дата:
1978-06-01
Аннотация:
Studies of magnetic viscosity in Au-Fe alloys containing 2 at.% and 7 at.% Fe are presented. The time decays of the remanences IRM and TRM are given for a range of temperatures up to and including the spin glass temperature, T<sub>f</sub>. All the decays are best described by the relation M=M<sub>0</sub>-Snlnt. S<sub>TRM</sub>(T), S<sub>IRM</sub>(T) both have maxima at 0.6 T<sub>f</sub>. The IRM data suggests a linear relation between S and M<sub>0</sub>. Plots of S/M<sub>0</sub>=V against T suggest the existence of two regimes of temperature below T<sub>f</sub>: (1)T<or=0.8 T<sub>f</sub>, V<sub>IRM</sub> nearly constant, independent of T, and much larger than V<sub>TRM</sub>. (2) 0.8<or=T<or=T<sub>f</sub>, both V<sub>IRM</sub> and V<sub>TRM</sub> strongly dependent on T and of nearly the same magnitude. These results at low temperatures can be qualitatively reproduced using a very simple activation model for noninteracting fine particles.
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