Granular L10 FePt (0 0 1) thin films for Heat Assisted Magnetic Recording

Granular L10 FePt (0 0 1) thin films were deposited on a Si substrate with Ta/MgO underlayers by rf sputtering. The effects of in-situ heating temperatures (350–575 °C), pressures (2–40 mTorr), and sputtering powers (15–75 W) on texture and microstructure were investigated for the FePt films. We obtained films with grain densities approaching 50 teragrains per in.2, grains sizes down to 2.2 nm with center-to-center spacing of 4.2 nm and coercivity of 24 kOe. The order parameters for the L10 FePt thin films were derived and calculated to be as high as 0.91. Although the grain size is small, the spacing between grains is too large for practical heat assisted magnetic recording media. To reach the desired results, we propose that layer-by-layer growth should be promoted in the FePt layer by inserting another underlayer that provides a better lattice match to L10 FePt.

Research highlights
► Granular L10 FePt (0 0 1) thin films were deposited on a Si substrate with Ta/MgO underlayers by rf sputtering.
► The effects of in-situ heating temperatures (350–575 °C), pressures (2–40 MTorr) and sputtering powers (15–75 W) on texture and microstructure were investigated for the FePt films.
► We obtained films with grain densities approaching 50 teragrains per in.2, grains sizes down to 2.2 nm with center-to-center spacing of 4.2 nm and coercivity of 24 kOe.
► The order parameters for the L10 FePt thin films were derived and calculated to be as high as 0.91.
► Although the grain size is small, the spacing between grains is too large for practical heat assisted magnetic recording media.