Magnetic Recording

Cobalt is an essential metal for the process of magnetic recording - a technology that is utilised in data recording devices such as hard disk drives.

Cobalt is often found in the medium used in magnetic recording devices, usually in the form of iron-cobalt. When in contact with an electro-magnet field the metallic grains can be polarised in one direction. Eventually the medium will migrate back to the previous chaotic state however.

Computer hard disk
Cobalt is an essential metal in data recording devices such as hard disk drives

A magnetic head (transducer) and the recording medium move in relation to one another. During recording, a varying current applied to the transducer coil, induces a magnetic field which magnetises a small region of the ferromagnetic recording medium. On play back, the varying magnetic fields on the tape pass the coil of the transducer and reverse the process by inducing varying voltages in the coil. Quality in this area is measured by how close the output is to the original input (i.e. high fidelity).

The same magnetic recording principles occur in hard disk drives where cobalt can also be found.