Colossal magnetoresistance

Colossal magnetoresistance (CMR) is a property of some materials, mostly manganese-based perovskite oxides, that enables them to dramatically change their electrical resistance in the presence of a magnetic field. The magnetoresistance of conventional materials enables changes in resistance of up to 5%, but materials featuring CMR may demonstrate resistance changes by orders of magnitude.

This technology may find uses in disk read-and-write heads, allowing for increases in hard disk drive data density. However, so far it has not led to practical applications because it requires low temperatures and bulky equipment.