High Refractive Index Protective Film BaTiON for Magneto-Optical Disk

Abstract

A new protective and enhancing film, BaTiON, is developed for magneto-optical memory media. The BaTiON film has exellent optical properties, with an refractive index (n) and a extinction coefficient (k) of 2.75 and zero, respectively.RF magnetron sputtering was used in the film preparation. The film is deposited using an argon-nitrogen mixed gas and a BaTiO₃ target. It is analyzed by XPS, EPMA, XRD, and RHEED. The analyses show that the BaTiON film is amorphous and consists of Ti_xO_y, BaO, and TiN_x. The composition ratio is Ba : Ti : O : N =1.0 : 1.0 : 2.6 : 0.1. The reflective layer type media used in the BaTiON film showes exellent reading characteristics and high writing sensitivity. The C/N is 49 dB and the writing power is 5.5 mW, when the linear velocity is 11.4 m/s and the recording frequency is 7.4 MHz.