Magnetic viscosity effect in ac susceptibility measurements
Journal
Physical Review B
Journal Volume
57
Journal Issue
1
Pages
92-95
Date Issued
1998
Author(s)
Abstract
The linear and nonlinear initial ac susceptibilities of thermally relaxing particulate media are derived perturbatively from a master equation. A distribution of activation energies endows the real part of linear susceptibility with a logarithmic dependence on frequency in analogy to magnetic viscosity in dc fields, the proportionality constant is found to be only weakly dependent on temperature via its dependence on thermal stability of the equilibrium state. The temperature and frequency range of this ac viscosity effect are enhanced by ferromagnetic coupling and the predicted behavior is compared with experimental data for (Formula presented) granular films. © 1998 The American Physical Society.
SDGs
Type
journal article