MEASUREMENT OF MAGNETIC VISCOSITY IN A STONER-WOHLFARTH MATERIAL

A Stoner-Wohlfarth model has been used to simulate conventional magnet ic viscosity experiments. The magnetic viscosity parameter Lambda was found to vary depending on the method used for measurement of the irre versible magnetisation. The difference in Lambda is found to be relate d to a parameter eta which describes the dependence of reversible magn etisation on irreversible magnetisation. The correct value of Lambda a t any field has been related to the population of particles which reve rse at that field and it is revealed that distributions of volume and orientation can obscure the interpretation of the measured Lambda. Thu s the measurement of Lambda as an indicator of reversal mechanism is q uestioned.