Preparation of LIPS (Longitudinally oriented Inside and Perpendicularly oriented at Surface) Dual Oriented Tapes Using Co-γ-Fe2O3

In order to improve the dual layer structure of LIPS tapes, by improving the perpendicularity of the surface layer and the longitudinal orientation of the inside layer, infrared irradiation under a perpendicular holding field was added to the "surface air-dry" stage. A tape thus obtained showed a higher playback output at both short and long wavelengths than for previous tapes with an oblique orientation over their entire thickness. The dual-layer tape had a playback output higher by 5 dB than for longitudinal tape at λ = 0.7 μm. Particles with a small aspect ratio (approximately 5) proved to be suitable for use in perpendicular tapes because of their resistance to calendering disorientation. This effect was confirmed by SQRz measurements.