Preparation of LIPS (Longitudinally oriented Inside and Perpendicularly oriented at Surface) Dual Oriented Tapes Using Co-γ-Fe 2 O 3

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.