Analysis of magnetic behavior of exchange-enhanced SmFeCo magnets

A series of densified exchange-enhanced SmFeCo magnets was produced by mech anical alloying, followed by a heat treatment. The nanocrystalline phases a nd the grain size distribution of the samples were characterized from x-ray diffraction patterns. Magnetic measurements in terms of different models w ere analyzed for the temperature behavior of the magnetization and coercivi ty. One analytical formulation was derived from the random anisotropy model predicting that with increasing M-r/M-s ratio a decreasing coercivity occu rs. Another numerical approach, which is based on a micromagnetic calculati on using finite element techniques was also applied. Attempts were made to improve the existing model derived from the finite element technique. The n ucleation model was found to be unsatisfactory for describing the temperatu re-dependent coercivity. (C) 1998 American Institute of Physics. [S0021-897 9(98)43011-1].