Patterned self assembled nanomagnetic arrays for massive data storage applications.
Ramanujan, R. V.
Date of Issue2003
School of Materials Science and Engineering
The projects which were undertaken under the scope of this work consisted of two themes (a) patterned self assembly of magnetic media for recording media and (b) the development of novel soft nanomagnetic materials which can be used as read/write heads or as underlayers. In the area of patterned self assembly of magnetic media for recording media, controlled self assembly of magnetic nanoparticles in various size and shapes has drawn tremendous interest as it offers a convenient tool to develop high density data storage devices. Patterned magnetic nanostructures have been fabricated using chemical synthesis techniques. Template assisted assembly of cobalt and cobalt ferrite "nanobowls" in a periodic arrangement with sufficiently high coercivity values for data storage applications has been achieved using colloidal crystal templating. Cobalt nanowires have also been synthesized by applying an external magnetic on cobalt nanoparticles showing the effect of shape anisotropy on magnetic properties. Elongated nanostructure of cobalt was also synthesized by fragmentation of "rod" to chain" shape transition due to Rayleigh instability effects. Nanowire arrays of cobalt and cobalt iron alloys have been chemically synthesized by an anodized aluminum oxide (AAO) template assisted assembly technique. The effect of textured growth on magnetic properties has been evaluated. These chains showed the effect of shape anisotropy on magnetic properties. Reverse micelle synthesis of cobalt nanoelements in various shapes has also been conducted and characterized.
DRNTU::Engineering::Materials::Microelectronics and semiconductor materials