PMR - Perpendicular Recording

- Sebastian Evers

The PMR technology, also called "vertical recording", is primarily used in hard disk technology. With this magnetic storage technology, all magnetic moments are aligned perpendicular (perpendicular) to the data carrier surface. Each magnetic moment represents a logical bit. In contrast to the horizontal (longitudinal) notation, the vertical data enables a much higher data density.

Due to the superparamagnetic effect - which means that the alignment based on the ferromagnetic property (depending on particle size and material used) can no longer be maintained with an adjacent thermal pulse - the previously used longitudinal recording technology was already at a data density of approx. 15 to 30 gigabits limited per square centimeter. The change of adjacent bits due to their proximity to the bit to be changed with a small particle size inevitably entails data loss. The data density could be tripled by the perpendicular-recording technique.

The possibilities of PMR technology were exhausted to the maximum in 2013. The high field strength required for magnetization also increased the risk of also writing to the adjacent storage units.