Effect of N2 additive gas during sputtering on magnetic properties and microstructure of CoB/Pd multilayered media

Effects of N2 additive gas and/or substrate heating during the sputtering of [CoB/Pd]20 multilayered films on the magnetic properties and microstructure were investigated. The [CoB/Pd]20 film fabricated at 20°C by adding N2 gas during sputtering possessed the finest grain size and the smallest magnetic cluster size among media fabricated in this study although the film sputter-deposited at 260°C by adding N2 gas exhibited the weakest intergranular exchange coupling. It was revealed that the double-layered perpendicular magnetic recording medium that consisted of the [CoB/Pd]20 film fabricated at 20°C by adding N2 gas exhibited the highest signal-to-noise ratio in the read–write characteristics.