FePt alloys with the CuAuI L10-ordered structure are important magnetic materials since their large uniaxial magnetocrystalline anisotropy can overcome the thermal stability problem of high-density magnetic recording media. In this study, transmission electron microscopy (TEM) and energy-filtered TEM (EFTEM) are employed to characterize the microstructure of a series of FePt/MgO multilayered thin films with different FePt layer thicknesses. The as-deposited FePt layers transform into the L10-ordered phase after annealing at 700oC for 30 minutes. The laminated FePt/MgO structure effectively preserves a strong L10 [001] texture normal to the thin film plane during annealing. The annealed films exhibit large coercivities from 6.5 kOe to 11.5 kOe due to the formation of the L10-ordered phase. A reduction in coercivity with increasing FePt layer thickness is attributed to the differences in the microstructure after annealing. For the films with thinner FePt layers, annealing produces discontinuous FePt layers that reduce exchange coupling and increase coercivity. As the FePt layer thickness increases, the magnetic layers become more continuous after annealing and thereby the exchange coupled layers have lower coercivity.
| Identifer | oai:union.ndltd.org:VANDERBILT/oai:VANDERBILTETD:etd-12012006-014151 |
| Date | 11 December 2006 |
| Creators | Fu, Yang |
| Contributors | James E. Wittig, James Bentley |
| Publisher | VANDERBILT |
| Source Sets | Vanderbilt University Theses |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.vanderbilt.edu/available/etd-12012006-014151/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Vanderbilt University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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