Temperature dependence of the magnetic viscosity parameter

The temperature dependence of the magnetic viscosity parameter Lambda, also known as S-v, has been examined using two theories based on thermal energy barrier activation and thermally induced fluctuation fields. For aligned, non-interacting Stoner-Wohlfarth particle assemblies it is shown that both theories predict the same temperature dependence for Lambda but that Lambda proportional to T or T-1/2 depending on how the field at which Lambda is measured is varied with temperature. It is also shown that for other mechanisms other temperature variations are possible. (C) 1998 Elsevier Science B.V. All rights reserved.