|
|
Ferromagnetic and superparamagnetic ordered nanoparticles configurations
|
|
Contract no: 71-119 / 2007
Contact: Dr. Ioan-Ovidiu Pana |
Results Stage I Stage II Stage III Stage IV Stage III
It was accomplished the correlation between the XRD diffractograms of the FePt and CoPt nanoparticles with the TEM results. The FePt alloy thermally treated sample and untreated sample were analyzed by X ray absorption technique. The local structure was determined by EXAFS. By TEM it was obtained the diameter distribution of the nanoparticles. The physical-chemical characteristics of the ordered structures of superparamagnetic nanoparticles within porous alumina matrix, were studied by XPS. An experimental model of laboratory method for compositional analysis of the magnetic nanoparticles of FePt alloy was made.
Two sets of samples of magnetic nanoparticles dispersed in polystyrene and in porous alumina matrix, were analyzed by XPS spectroscopy. The depth profile analysis evidenced the formation of nanotubes having dispersed the magnetic nanoparticles . For the FePt samples, the untreated and thermally treated, the magnetization versus the applied magnetic field was studied. In the first case it was evidenced the superparamagnetic behavior of the nanoparticles, having a reduced magnetization and a very small coercitive field. For the thermal treated alloy it was evidenced the formation of the L10 faze, by the high coercitive field and the increase of the magnetization by two orders. It was accomplished the correlation between the magnetization and the synthesis conditions.
The Mossbauer spectra of Fe within the FePt nanoparticles was obtained and analyzed for the thermal treated sample and the untreated. It was evidenced the formation of the ordered phase L10.
|
