Exchange coupling and energy product in random two-phase aligned magnets

Size effects in two-phase Boolean magnets composed of an aligned hard phase and a soft phase with high magnetization are investigated. In 'overcritical' magnets, where the size of the soft regions is larger than the Blochwall width /spl delta//sub h/ of the hard phase, the energy product is reduced compared to the corresponding 'undercritical' magnets with small soft regions, where theoretical energy products as high as 1 MJ/m/sup 3/ have been predicted. Nevertheless, the theoretical energy product only gradually drops with increasing size of the soft regions, and it may still exceed the theoretical energy product 516 kJ/m/sup 3/ of Nd/sub 2/Fe/sub 14/B.<
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