Investigation Of Ultra-high Density Magnetic Recording Thin Film Media Materials

Magnetic reacording media materials are one of the key materials in ultra-high density magnetic storage technology, which play an important role to enhance the magnetic recording areal density.The rare earth-transition metal PrCos phase and L10-FePt alloy with large magnetocrystalline anisotropy Ku, high coercivity Hc, and strong saturation magnetization intensity Ms are suitable for the ultra-density magnetic reacording media materials. It is hard to obtain single PrCos phase for avoiding to the soft magenetic phases of Pr.5Co19and Pr2Co17. As-deposited FePt film is dis-orderly fcc phase which is soft magnetic. It must be processed at high temperature to get the ordered fct phase with hard magnetic(Llo-FePt alloy). One of the key challenges is how to obtain the applicable single PrCos phase with hard magnetic and how to get L10FePt film with perfect (001) orientation and outstanding perpendicular anisotropy.In this paper, Pr-Co intermetallic alloy and FePt/E4C composited thin film have been investigated. The thesis includes two parts:1Investigation of Pr-Co thin films on phase formation, micro-structure, and magnetic propertiesWe have prepared the Pr-Co film with various annealing temperature and annealing time by magnetron sputtering. Although the atomic ratio of Pr:Co is close to1:5, the thin films indicate a multi-phase co-existence of PrCos, Pr2Co17and Pr.sCo1q no matter the annealing temperature and annealing time. However, the hard magnetic PrCo5is favorable to form at annealing temperature≥600℃and relatively short annealing time. Sample with a coercivity of5.9kOe and high squareness of0.8was obtained by annealed at600℃for10mins, in which the hard magnetic PrCo5is the dominant crystallographic phase.2Effect of magnetic field annealing on microstructure and magnetic properties of Pr-Co thin films in vaccumFePt thin films with atom ratio of Fe:Pt=53:47have been prepared by magnetron sputtering. Effect of the thickness of FePt magnetic layer, different percentage of doped B4C, and various annealing conditions on microstructure and magnetic properties were investigated. And we further studied the microstructure and properties of the sample after annealing in vaccum with magnetic field perpendicular to the films surface. The films with perfect (001) orientation and outstanding perpendicular anisotropy have been obtained. The optimum results:perpendicular orientation coercivity value of6.7KOe and minimum grain size of11.18nm were observed, which are the required for ultra-high density magnetic recording media materials.