Preparation of LIPS(longitudinally oriented inside and perpendicularly oriented at surface) dual oriented tapes using Co-.GAMMA.-Fe2O3.

In order to improve the dual layer structure in the LIPS tape preparation, i.e. more perpendicular surface layer and more longitudinal inside layer, an infrared radiation was added in the “surface air dry” stage under a perpendicular holding field. An attained tape shows higher reproduction output both in short and long wavelengths in comparison with our former tape with oblique orientation in full thickness. The dual layer tape shows a 5 dB higher reproduction output than a longitudinal tape at λ = 0.7 μm. Small aspect ratio (∼5) particle proved to be suitable for perpendicular tape because of its resistivity against calendering redisorientation. This effect is confirmed from SQRz measurement.