As we enter the information epic, demands for higher data storage density in magnetic hard disks escalate drastically.  However, the storage density of current thin film magnetic disks is approaching the fundamental limit set by the properties of the magnetic thin film.

  But, many factors that limits the storage density of conventional magnetic recording media can be eliminated or alleviated, if the continuous, thin-film media is abandoned and replaced by a new paradigm for magnetic disks, quantized magnetic disks (QMDs).  QMDs have pre-fabricated, discrete, single-domain magnetic elements uniformly embedded in a nonmagnetic disk. Each magnetization direction of a single-domain element represent a bit of binary information.  A QMD of a vertical magnetization uses pillars (Fig. 1) and a longitudinal magnetization uses bars (Fig 2).  The magnetic field needed to switch the magnetization direction can be controlled by engineering the element's size and shape anisotropy.

  QMD's have many advantages over the conventional disks such as spontaneous self-quantization of each bit's magnetization and a quantized writing process to reduce requirements of the write head and the head position accuracy; small, smooth, isolated transition region allowing high data packing density and near zero transition noise; built-in tracking makes for precision tracking and position of write/read heads, and overcomes the superparamagnetic limits.