Heat-assisted magnetic recording

Heat-assisted magnetic recording (HAMR) is a magnetic storage technology for hard drives in which a small laser is used to heat the part of the disk that is being written to. The heat changes the magnetic properties (its "coercivity") of the disk for a short time, reducing or removing the superparamagnetic effect while writing takes place. This magnetic effect sets a limit on the areal density of magnetic recording (how much data can be stored in a given area of a disk). The effect of HAMR is to allow writing on a much smaller scale than before, greatly increasing the amount of data that can be held on a standard disk platter.