C (ti) / Fept / Ti (fe) Microstructure And Magnetic Properties Of A Series Of Film Samples

The FePt Ll₀-phase-ordered alloy thin films were regarded as hopeful candidates for ultrahigh magnetic recording media because of their high magnetocrystalline anisotropy. Some key issues for the application of Ll₀-FePt films remained to be solved: decreasing the ordering temperature, magnetic particles were separated by nonmagnetic particles and uniform, orientation. In this thesis, FePt, FePt/Ti, C/FePt/Ti, C/FePt/Fe, and Ti/FePt/Fe films were fabricated using dc facing-target magnetron sputtering system onto glass amorphous substrates. Their physical properties were studies systemically with XRD, PPMS, VSM, and SPM.For Fe₄₈Pt₅₂ film, the as-deposited film was disorder fcc phase, the ordered Llo texture had begun to be formed at T_α = 500 ℃. When annealed at 650 ℃, it were obtained that the great ordered Ll₀ phase, about 12.4 kOe huge coercivity and closed to 1 squareness degree.For FePt (30 nm)/Ti (t₁ nm) films, we found that FePtTi could be formed at t₁ < 5 nm, and the interaction among grains were primarily ferromagnetic exchange coupling action. At t₁ = 1 nm, there were 12.1 kOe coercivity and the weaker intergrain interaction. Moreover, the Ti underlayer played important roles in reducing annealing temperature. From the active volume analyzing, it was found that magnetization reversal process was mainly magnetization rotation. By the △ m method, ferromagnetic exchange coupling action was the leading interaction between grains for FePt (30 nm)/Ti (1 nm) films and was weakest when annealed at 600 ℃.It was found that C cover layer could separate particles, reduce the particles size, and induce the ordered Llo texture formed. A huge coercivity over 13.681 kOe, saturation magnetization about 679 emu/cc and squareness approach 1 were obtained in C (12 nm)/FePt (30 nm)/Fe (1 nm). From analyzing of remnant magnetism, the intergrain interaction was decrease with increasing the C cover layer thickness.In addition, Ti cover layer could increase the degree of Llo ordered texture, decrease the interaction between grains, decrease the size of grain and particle, and improve the magnetic properties. Besides Ti with FePt form the ternary alloy, it form alloy of cubic structure with Fe and Pt, PtTi3 and FeTi.