Title :
Co-deposition of FePt and CoPt nanoparticles on silicon dioxide
Author :
Castaldi, L. ; Giannakopoulos, K. ; Travlos, A. ; Niarchos, D. ; Boukari, S. ; Paire, E. Beaure
Author_Institution :
NCSR "Demokritos", Attiki, Greece
Abstract :
In this study, Fe50Pt50 and Co50Pt50 nanoparticles are prepared by electron beam evaporation by co-deposition on thermally oxidized silicon (100) substrates with a SiO2 amorphous layer of 90 nm on top. The samples are deposited at a substrate temperature Ts ∼ 750°C and with a nominal thickness of the layer of 8.5 nm. Annealing of the samples is done at 750°C immediately after deposition. The structural and morphological properties are analyzed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The compositional map of selected samples is obtained by electron energy loss spectroscopy (EELS) and the quantitative chemical characterization is performed by energy dispersion X-ray analysis. The magnetic properties of the nanoparticles are measured using a magneto optical Kerr effect magnetometer at room temperature. XRD patterns indicate that the as-deposited samples are in the cubic phase with a (111) texture. Increasing the annealing time results in the progressive crystallization of the Ll0 ordered phase with a (111) texture and in the progressive magnetic hardening of the samples with the maximum coercivity of ∼ 7.4 kOe.
Keywords :
Kerr magneto-optical effect; X-ray chemical analysis; X-ray diffraction; annealing; cobalt alloys; coercive force; crystallisation; electron beam deposition; electron energy loss spectra; iron alloys; magnetic particles; nanoparticles; nanotechnology; platinum alloys; transmission electron microscopy; (111) texture; 20 degC; 750 degC; 8.5 nm; 90 nm; Co50Pt50; Fe50Pt50; Ll0 ordered phase; SiO2; X-ray diffraction; annealing; co-deposition; coercivity; crystallization; cubic phase; electron beam evaporation; electron energy loss spectroscopy; energy dispersion X-ray analysis; magnetic hardening; magneto optical Kerr effect magnetometer; nanoparticles; transmission electron microscopy; Amorphous magnetic materials; Annealing; Chemical analysis; Electrons; Iron; Magnetic analysis; Nanoparticles; Silicon compounds; Temperature; X-ray scattering;
Conference_Titel :
Magnetics Conference, 2005. INTERMAG Asia 2005. Digests of the IEEE International
Print_ISBN :
0-7803-9009-1
DOI :
10.1109/INTMAG.2005.1463520