POLARIZED NEUTRON REFLECTOMETRY ON A 2-LAYER ME TAPE

Commercially available two-layer metal-evaporated videotape (compositi on Co71Ni16O13) was brought into various remanent magnetic states by a wide recording head or by applying a perpendicular field. The polariz ed neutron reflectivity (PNR) of the tape in the various states has be en measured. As PNR is sensitive to the magnetization as a function of depth, this technique enlarges the understanding of the writing proce ss. The measurements were fitted simultaneously, keeping the nuclear s tructure the same for the different magnetic states. The model fitted to the measured data clearly shows two magnetic regions, It is also be yond doubt that the recorder head writes a signal through the whole de pth of the tape. The model clearly shows the opposite easy axes in the in-plane direction of the separate layers after perpendicular magneti zation.