HAMR - Heat-Assisted Magnetic Recording

- Sebastian Evers

As part of the constant increase in data density, hard drive manufacturer Seagate relies on HAMR technology ("heat-assisted magnetic recording"). The technology takes advantage of the physical peculiarity of magnetizable materials. This effect makes it possible to magnetize magnetic substances with heating far beyond a certain temperature value, even with a significantly lower field strength.

The reduction in magnetic field strength that can be achieved in this way makes it possible for the individual storage units to be arranged even closer to one another; without the problem of superparamagnetism. Using a laser implemented in the read/write head, the respective storage unit is brought to the required temperature selectively and then magnetized by the write head. Due to the immense heat pulse, it is also necessary that thermally resistant materials for magnetization, with a correspondingly high coercive field strength, serve for permanent magnetization. Otherwise, the high heat pulse could result in complete demagnetization of the material.