Multiple small angle neutron scattering in ferromagnets

The conclusions arising from the multiple small angle neutron scattering theory, developed recently by S.V. Maleyev, R.V. Pomortsev and Y.N. Skryabin [Phys. Rev. B 50 7133 (1994)] for the value of Born parameter more than 1, are experimentally confirmed by magnetic scattering from domain structure of pure Fe and Ni, as well as Fe_{65}Ni_{35} alloy. The crossover from multiple refraction to multiple Fraunhofer diffraction is found to be at a critical thickness L_0, where dependence of the neutron beam broadening w on sample thickness L changes from law L^{1/2} to law L.Comment: 2 pages, latex, espcrc2.sty, 2 figures; to appear in the Proceedings of the 1st European Conference on Neutron Scattering, Physica