In a real magnet, the relation between isothermal remanence and dc demagnetization remanence is expressed as It is believed that nonzero is due to the interactions between particles in the magnet. Using as a sample, the relation is examined by the micromagnetic finite element method. The positive value of is primarily caused by intergrain exchange coupling. The decrease of intergrain exchange coupling results in the drop of the maximum value of However, the variation of anisotropy in grain boundaries produces no change in the maximum value of A Henkel plot is suggested to be effective for checking intergrain exchange coupling in magnets.
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