Reducing the Writing Temperature of Thermal Assisted Media by Controlling the Composition of FePt

Twenty-nanometer FePt films with 40% Fe content were deposited on MgO substrates at 300degC. A perfect (001) preferred orientation of FePt L1₀ phase was obtained. After 700degC annealing in vacuum, a room temperature perpendicular anisotropy of as high as 4.5times10⁷ erg/cm³ can be obtained. The Curie temperature of the sample with 40% Fe content is far below the 50% Fe sample, which can effectively reduce the temperature of the thermal writing process. Furthermore, decay of magnetic anisotropy energy (K_u) is much faster than saturated magnetization (M_s ) with rising temperature, which results in a domination of demagnetization (DM) energy at high temperature. Therefore, a further reduction of the switching field can be achieved. Finally, the films show almost the same magnetic properties during 10 times thermal writing processes from 25degC to 300degC, implying this media has high reliability for thermal writing process