Co-Mo and Co-Mo-Cr alloy thin films promising for magnetic recording

Phase separation behavior of Co-Mo thin films and magnetic anisotropy energy of Co-Mo and Co-Mo-Cr thin films deposited on Cr(112)//MgO(110) single crystal substrates have been studied by using an analytic transmission electron microscope and a vibrating sample magnetometer. The results show that the phase separation does happen in the Co-Mo thin films, resulting in Mo-rich phase surrounding Co-rich magnetic grains, similar as that in the Co-Cr system. However, the Mo-rich phase still shows the ferromagnetic characteristic at room temperature due to its not so high Mo content. The first order anisotropy constants of the Co-Mo thin films are about double that of the Co-Cr thin films in the composition range of 4.0-14.0 at.%Mo (or Cr). With the addition of Cr into the Co-8.7 at.%Mo thin film, the magnetic anisotropy constants show no obvious deterioration, but it results in the increase of anisotropy field.