Rotation of neutron spin in passing through a noncentrosymmetric single crystal

Rotation of the spin of cold neutrons passing through a noncentrosymmetric single crystal is observed. This effect is caused by the Schwinger interact ion of the magnetic moment of a moving neutron with the crystalline electri c field in a noncentrosymmetric single crystal and depends both on the dire ction of neutron trajectory in the crystal and on its energy. It is shown t hat the characteristic magnitude of the effect for alpha -quartz is similar or equal to (1-2) x 10(-4) rad/cm over a wide wavelength range (from 2.8 t o 5.5 Angstrom) and is determined by the degree of beam monochromaticity [D elta lambda/lambda = (2-5) x 10(-2) in our experiment]. This magnitude corr esponds to an electric field of similar or equal to (0.5-1) x 10(5) V/cm ac ting on a neutron. The measured value agrees well with the theoretical calc ulation. (C) 2001 MAIK "Nauka/Interperiodica".