Neutron spin rotation effect at Laue diffraction in a weakly deformed and nonabsorbing crystal with no center of symmetry

Abstract

The effect of the neutron spin rotation at Laue diffraction in a weakly deformed noncentrosymmetric and transparent for the neutrons crystal has been theoretically described and experimentally investigated. This effect arises in the deformed crystal because of the curvature of the neutron trajectory in the crystal. A certain type of deformation leads to the escape outside the crystal of one of the two neutron waves excited at Laue diffraction. This two waves propagate in the crystal without a center of symmetry in electric fields with the opposite sign. In this case the spin of the remaining neutron wave will be rotating relative to the original direction due to the interaction of the magnetic moment of the moving neutron with the crystal's intracrystalline electric field. In a perfect undeformed crystal such spin rotation effect is absent. There is only a depolarization of the beam since both waves in opposite electric fields are present with the same amplitudes. A technique for controlled deformation of a perfect single crystal by creating a temperature gradient has been developed. Thus a new possibility to measure the electric fields which act on the neutron in noncentrosymmetric crystals has been realized. There also appeared a way to control these fields in experiments on the study of the neutron fundamental properties.