High Temperature Stability of Magnetic Clusters
Abstract
We studied and synthesized magnetic single domain particles, improved the resolution of magnetic force microscopy (MFM) tips for magnetic domain imaging and studied both experimentally and theoretically the magnetization reversal process in nanostructured materials. CoPt thin films with well-separated 1OO-200nm crystallites of well-ordered fct structure were achieved by controlling the annealing time and annealing temperature. Our CoPt films show magnetic coercivity up to 37kOe which is the highest coercivity ever observed in this system. We used CoPt for coating magnetic force microscopy tips. We observed better-resolved magnetic images of a reference recording disk taken with CoPt MFM tips. We also developed advanced magnetic beam microscopy tips using focused ion beam milling to obtain higher resolution in magnetic images. We have shown that the magnetization reversal behavior depends strongly on the magnetic field dependence of the energy barrier to thermally-activated reversal. The model calculations carried out thus far predict temperature dependent "activation volumes" similar to those measured in such materials as CoSm thin particulate films and Co/Au multilayers. These studies have significant implications for high temperature magnetic stability and for long-term stability of magnetic data storage media.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 14, 2001
- Accession Number
- ADA388366
Entities
People
- Roger D. Kirby
- Sy-hwang Liou
Organizations
- University of Nebraska–Lincoln