Investigation of FePt-SiO2-C granular film in columnar structure

Abstract

We worked on a FePt granular film with a columnar structure, for the purpose of ultrahigh density perpendicular magnetic recording media. In experiments, a Fe53Pt47-SiO230%-C25% (10 nm) film was deposited on a silicon substrate with a MgO (12 nm) interlayer at 510 °C. The perpendicular coercivity of the film is 29 kOe, with a squareness of 1. Bright-field TEM images show that the FePt granular film has small and uniform grains of 8.3 ± 1.9 nm with a columnar structure. More work of high-resolution TEM imaging shows excellent L10 ordering inside the FePt grains. The measurement of remnant coercivity proves that it has an energy barrier of 290kBT at room temperature, meaning excellent thermal stability. We demonstrate FePt granular film to be a qualified candidate for high-density perpendicular magnetic recording media, and both SiO2 and C addition helps form columnar structure.