Lowering aspect ratio of patterned islands to achieve ultrahigh storage densities

Patterned islands with high aspect ratio are easier to form single domain state due to the shape anisotropy. However, simply increasing the aspect ratio would not be an ideal way in a single-bit-per-island recording system because achieving ultrahigh storage densities and high data transfer rate will rely on being able to make narrower elements, with a lower aspect ratio, as close together as possible. In this work, it is found that a magnetocrystalline anisotropy down track oriented medium with narrow anisotropy angular distribution is preferred for patterned polycrystalline cobalt islands to form a uniform single domain demagnetized state with smaller aspect ratio than one with broad anisotropy angular distribution.