Measurements with a VSM

The last 50 years have seen the development of methods for the digital storage of information. The current method for the storage of digital information is predominantly through the use of magnetic media. Increasing media storage density continues to be a very active area of research. Magnetic media may be divided into particulate and continuous media. Particulate media are comprised of small magnetic particles bonded on a plastic tape or disk, the thickness of the magnetic overcoat is typically on the order of 10,000 Å. Since these are single domain particles, the information is stored by inverting the magnetization of some of the particles. Continuous media are metallic thin films, typically a few hundred angstroms in thickness. Particulate media are advantageous in that they are relatively simple to prepare and are chemically stable, however their recording density is relatively low. Continuous media on the other hand have higher storage densities and the shapes of their hysteresis loops (and hence recording characteristics) may be varied in a controlled way.