Abstract
In this study amorphous aluminum oxide (α-AlO) was used as an underlayer to crystallize c-axis oriented Ba-ferrite (BaM) film. But coercivity of these films was going to decrease sharply below 20 nm. A small amount of Al is added with BaM film with α-AlO underlayer. The substrate temperature (Ts) was kept at 550°C. Al content was varied from 0-4.5 atomic percent. Perfect c-axis orientation of BaM thin film is possible with a small addition of Al, even for the film of 10 nm with a δθ50 of 2.5°-2.8°. On the other hand, it was difficult to crystallize BaM/α-AlO film thinner than 25 nm. Coercivity of Al-BaM/α-AlO films in perpendicular direction was higher than that of BaM/α-AlO films, even for the thickness below 20 nm.
