Self-Stabilized Carbon-L1(0) FePt Nanoparticles for Heated Dot Recording Media

Abstract

Heated dot magnetic recording (HDMR) technology promises to achieve ultrahigh storage density well above 4 Tb/in(2) by making use of L1(0) FePt bimetallic islands HDMR media require the development of thermally stable, noninteracting magnetic patterns to circumvent the signal noise and writability challenges We prepared self-stabilized carbon-L1(0) FePt nanoparticles (NPs) with average diameter of about 7.2 nm for the HDMR media FePt NPs synthesized by chemical reduction using oleic acid and oleylamine transform to the carbon-L1(0) FePt phase with optimized heat treatment at 873 K. The high-temperature annealing not only helps to achieve the desired L1(0) phase but also helps in the formation of a carbon coating on the FePt NPs due to degradation of the organic cap We investigated the effect of carbon coating on the electronic states of Fe using X-ray absorption measurements and corroborated with high-resolution transmission electron microscopy and Fourier-transform infrared spectroscopy X-ray magnetic circular dichroism reveals the presence of magnetocrystalline anisotropy in the carbon-L1(0) FePt NPs, which is also supported by the structural and magnetic measurements A magnetization-field loop at 300 K shows high coercivity of approximate to 1.6 T. The synthesized carbon-L1(0) FePt NPs can be used as FePt islands and should be suitable for high-density HDMR media.