Calculation of strayfields near grain edges in permanent magnet material

The internal strayfields near the edges of permanent magnetic grains are calculated. A numerical algorithm has been developed to consider the modification of the strayfield resulting from the rotation of the magnetization from the easy axis in external and internal fields. Anisotropy constants of higher order are considered. The results are applied to Nd₂Fe₁₄B. The ratio between strayfield strength and saturation magnetization defines a theoretical local demagnetizing factor which is comparable with the effective demagnetizing factor used to describe the temperature dependence of coercivity. The effect of strayfields on the coercive field and its angular dependence is discussed.