SMALL-ANGLE SCATTERING OF POLARIZED NEUTRONS IN HTSC CERAMICS

The results of the first observation of the small-angle polarized neut ron scattering (SAPNS) from magnetic flux inhomogeneities in high-T-c Y-Ba-Cu-O and La-Sr-Cu-O ceramics are reported. The difference between the scattering cross sections for neutrons initially polarized along or opposite to the applied field was found at T < T-c and in the range of applied field below H-c1 of grain in ceramics. The alternative sig n effect was observed in remanent field trapped in grains after applyi ng a field. The effect is explained by nuclear-magnetic interference a nd is proportional to the Fourier transform of the cross-correlator of the magnetic-nuclear (MN) scattering length density fluctuations (SLD ).