Y. Kitamoto et al., Intergranular coupling and activation volume of Co-Ni ferrite thin films with high coercivity above 3 kOe, IEEE MAGNET, 35(5), 1999, pp. 2694-2696
Co-Ni ferrite film media with high coercivity above 3 kOe were fabricated b
y ferrite plating and intergranular coupling and medium noise were discusse
d. Increase of Co content in Co-Ni ferrite thin film with a thickness of 40
nm led to a decrease of intergranular exchange coupling and activation vol
ume, resulting in the reduction of media noise in the high frequency region
. The coercivity H-c increased with the Co content, and reached 3.6 kOe, At
the maximum Co content, the activation volume took the minimum value of 6.
7x10(-18) cm(3), being smaller than the volume of a single grain in the fil
m The medium noise was kept almost constant up to the linear recording dens
ity of 144 kfrpi, while the noise of the media with the lower Co content an
d lower H-c increased with the linear recording density.