Magnetic and Recording Characteristics of CoCrPt-Oxide Media With a Mixture of ${\hbox {SiO}}_{2}$ and ${\hbox {TiO}}_{2}$

We have investigated the capability of dual oxide by comparing the magnetic and recording characteristics of CoCrPt-oxide media with SiO
₂
, TiO
₂
, or a mixture of SiO
₂
and TiO
₂
. We found that CoCrPt-oxide films with a mixture of SiO
₂
and TiO
₂
have a higher coercivity, particularly at a low O
₂
partial pressure, than CoCrPt-oxide films with SiO
₂
or TiO
₂
. Media with SiO
₂
or a mixture of SiO
₂
and TiO
₂
have a higher signal-to-noise ratio (SNR) than that of media with TiO
₂
. The high SNR of the media with a mixture of SiO
₂
and TiO
₂
was obtained in narrower magnetic-core-width conditions than those of the media with SiO
₂
, suggesting that the dual oxide media have greater potential for areal density growth than the single oxide media. Transmission electron microscopy revealed that the dual oxide film has narrower and more uniform grain boundaries than the single oxide films. We believe that these microstructures will lead to higher packing density with reduced dispersion of intergranular exchange coupling, which is one possible reason for the improved recording performance.