ON THE DETERMINATION OF THE MAGNETIZATION DECAY OF A MAGNETIC FLUID WHOSE COMPLEX-SUSCEPTIBILITY DATA FITS A COLE-DAVIDSON PLOT

In this paper the magnetisation decay or after effect of a magnetic fluid, the complex susceptibility data of which fits the magnetic analog of the Cole-Davidson equation, was determined. In addition the data were fitted to the Cole-Cole and Havriliak-Negami equations to ascertain the impact of these equations on the magnetisation decay curve. It was found that whereas the plots of the decay functions for the Cole-Davidson and Havriliak-Negami cases were similar, particularly at high and low times, the decay function generated from the Cole-Cole equation differed substantially over the entire decay. However the Cole-Davidson had an additional advantage over the use of the other equations in that a continuous magnetisation decay curve could be generated. This was because no closed decay function exists in the other cases.