Thermal stability of anisotropic and isotropic Co alloy thin-film media is investigated. The orientation ratio of CoCrTa(Pt)/Cr media was controlled by the mechanical texture of the NiP/Al substrates. Bulk magnetic properties, delta M curves and time decay of magnetization in the circumferential and radial directions were measured. The maximum magnetic viscosity coefficient calculated from the time decay of magnetization in the circumferential direction was higher than that in the radial direction for a mechanically textured sample, while it was similar in both directions for a non-textured sample. The magnetic viscosity coefficient in the circumferential direction is smaller than that in the radial direction when the reverse field is in the range of the demagnetization field for thin-film recording media. This implies that an anisotropic sample (namely, a sample with a high orientation ratio) will be more thermally stable when it is not exposed to a large external magnetic field.

Post annealing treatment for CoCrPt magnetic thin films were tried in different thermal conditions, by changing the time of annealing procedure. Coercivity (Hc) improvement was achieved in annealed sample compared with those as deposited, in which as high as 5.2 kOe has been attained. To clarify the mechanism of annealing treatment on the magnetic properties, X-ray diffraction (XRD) spectrums of those samples and their magnetic properties were carefully studied. Co and Cr lattice parameters were separately calculated from different crystal lattice plane. It was found that a axis lattice spacing of Co hexagonal structure increases monotonically with increased annealing time. Variation of Co hcp peaks significance may due to Cr or Pt redistribution in the crystal grains and its boundaries. Combined with the grain size analysis of Co-rich area by X-ray diffraction peak broaden width, which was not very consistent with the result obtained from other's TEM and AFM studies, Cr diffusion was suggested to be the governing factor at short annealing time region. Co-rich grain growth should also be applied to explain the variation of magnetic properties in longer post annealing.

Triple-layer CoCrPt magnetic thin films with different bias configurations were fabricated by DC magnetron sputtering on CrV and glass substrate. In-plane coercivity (Hc) showed an increase for those films with bias sputtered CoCrPt layer. The in-plane coercivity (Hc) was optimized in NB-B-NB type film prepared with substrate heating at 300C (NB: no bias and B: rf bias applied in sputtering). Better in-plane crystal texture was observed in NB-B-NB type film by XRD and this is believed to be the main reason for the coercivity improvement. The other resource for the coercivity improvement was due to the decoupling of intergrain magnetic interactions. This was discussed accordingly to the results obtained from TEM, MFM and SIMS depth profiling.