Chemical synthesis of nanomagnetic arrays for information storage

• Main Author: Raju V Ramanujan
• Other Authors: School of Materials Science & Engineering
• Format: Research Report
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Materials::Nanostructured materials
• Online Access: http://hdl.handle.net/10356/17237
• Institution: Nanyang Technological University

The project which was undertaken under the scope of this work was the chemical synthesis of nanomagnetic media for information storage media, controlled self assembly of magnetic nanoparticles in various size and shapes has drawn tremendous interese 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 peoperties. Elongated nanostructures of cobalt were 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 been conducted and characterized in this work, cobalt nanoelements were synthesized in h.c.p., h.c.p. + f.c.c., f.c.c. crystal structures. Coercivity values in a cobalt ferrite and cobalt-iron alloys have also been synthesized with interesting properties and their magnetic properties were measured. A number of publications, invited conference talks, encyclopedia article, symposium chair recognition etc. have resulted from this work.