Data centers are currently relying heavily on HDDs that employ perpendicular magnetic recording (PMR) to store data at areal densities of approximately 1.5 Tbit/in². To transition to higher areal densities, a high anisotropy magnetic recording medium consisting of FePt grains combined with heat-assisted laser writing is necessary. This method, known as heat-assisted magnetic recording (HAMR), can sustain areal recording densities of up to 10 Tbit/in². Moreover, densities beyond 10 Tbit/in² are achievable based on a new principle demonstrated by storing multiple recording levels of 3 or 4 compared to the binary level used in HDD technology.
Three-Dimensional Recording
The researchers successfully arranged the FePt recording layers three-dimensionally by fabricating lattice-matched, FePt/Ru/FePt multilayer films, with Ru serving as a spacer layer. Measurements of the magnetization revealed that the two FePt layers possessed different Curie temperatures, enabling three-dimensional recording by adjusting the laser power during writing.