In hard disk drives, it is desirable to increase the density at which information is recorded on the disks as this leads to higher storage capacity and/or reduced cost. Currently the disk drive industry is facing a significant challenge in increasing storage density due to a problem of thermal stability: The very small volumes of magnetic material containing each bit of recorded information become unstable due to thermal agitation. A possible solution is to use a different material in the magnetic recording layer on the disk that has a larger anisotropy or coercive field. However, presently available materials used in magnetic recording heads cannot produce sufficient magnetic field to write on such high-anisotropy media. This technology provides a solution for this challenge.
Acoustically assisted magnetic recording can be used in a hard disk drive or a solid state medium. With this technology, otherwise unwriteable high-coercivity media are made amenable to recording by lowering their coercivity via strain induced by acoustic waves. The use of acoustic waves temporarily and locally reduces the magnetic field required to record information on a magnetic recording medium. The process makes use of the magnetostrictive property of a magnetic material by which the magnetic anisotropy of the material is changed by strain. The result of such a change is a reduction in the coercive field, i.e., the magnetic field required to reverse the magnetization direction. Because acoustic waves cause strain, the passage of an acoustic wave through a magnetic material can be used to reduce its coercive field.