Relationships between minor hysteresis loops and dislocation density were investigated at 10 to 600K in polycrystalline nickel with tensile deformation. It was revealed that coefficients obtained from scaling relations between parameters of minor-loops were in linear proportion to stress at all measuring temperatures below its Curie temperature. Considering that dislocation density was generally in proportion to the square root of true stress, it was concluded that the coefficients were related with the square root of dislocation density. This method using minor hysteresis loops was useful for quantitative evaluation of dislocation density because of its very low measurement field.

Quantitative Evaluation of Dislocation Density using Minor-Loop Scaling Relations. S.Kobayashi, T.Kimura, S.Takahashi, Y.Kamada, H.Kikuchi: Journal of Magnetism and Magnetic Materials, 2008, 320[20], e551-5