  We propose an explanation of the anomalous growth of plasticity in
ferromagnets near the Curie point. We demonstrate that this effect is caused by
spin-dependent detachment of dislocations from obstacles under an influence of
the internal magnetic field. Magnetization fluctuations grow in the vicinity of
the Curie point, yield an increase of the detachment probability and, hence, an
increase of the plasticity. We apply this model for a description of the
temperature behaviour of the critical stress in nickel and of the microhardness
of gadolinium. An external magnetic field suppresses the magnetization
fluctuations and, hence may suppress the above singularities.
