Neutron depolarisation in magnetic alumite disks for perpendicular recording

Polarized neutrons ( lambda =0.36 nm) are transmitted through magnetic alumite films prepared on disks of Al with 4 wt.% Mg. The depolarization results obtained as a function of transmission angle in two alumites with equal pore width but different cell width are analyzed. It appears that a strong antiparallel correlation between magnetization directions of neighboring iron-filled pores exists in the sample with the biggest pore width. In the less-dense sample, such correlation is not observed because in this case neighboring pores as seen along the neutron transmission direction are not nearest neighbors in the lattice of the alumite.