Thermal fluctuation field in RE-TM-B permanent magnet materials

The temperature dependence of the coercive field (H/sub c/) and the thermal fluctuation field (H/sub f/) of Nd-Fe-B sintered magnets was measured from 100 K to 500 K. It was found that a linear relationship exists between l/sub g/H/sub f/ and l/sub g/H/sub c/ in this temperature range. The relationship between l/sub g/H/sub c/ and l/sub g/H/sub f/ was deduced from Gaunt's localized weak pinning model. Values of l/sub g/H/sub c/ calculated from the derived relationship are in very good agreement with experimental values.>