Temperature dependence of switching properties of a 2-D array of Preisach-type particles

The temperature dependence of the “up” and “down” switching fields was measured magnetooptically for over a hundred individual, 40 μm×40 μm×3 μm “pixels”, etched into a garnet film and representing single domain particles. The best fit to the distribution of the coercivity of the “pixels”, i.e. of the width of the individual hysteresis loops, is a Gaussian. Its mean value and temperature dependence closely match the major loop coercivity, and its standard deviation is characteristic of the distribution of the “strength” of the defects responsible for the coercivity. The distribution of the interaction fields follows a Lorentzian function