XRD patterns of (a) as-synthesized and (b) annealed FePt nanoparticles at 600 °C for 1 h along with JCPDS #-29-0717 (fcc-FePt) andJCPDS #-43-1359 (fct-FePt) data file. (c) Williamson-Hall Plot for as-synthesized one.
FTIR spectrum of as-synthesized FePt nanoparticles coated with oleic acid and oleylamine.
(a) TEM image of as-synthesized fcc-FePt nanoparticles and (b) its HRTEM image showing lattice fringes.
(a) TEM image of annealed (at 600 °C) fct-FePt nanoparticles, and (b) its HRTEM image showing lattice fringes.
XPS spectra of as-synthesized FePt nanoparticle coated with oleic acid and oleylamine: (a) C 1 s, (b) O 1 s, (c) Fe 2 p, and (d) Pt 4f recorded at room temperature.
M vs H plots of the as-synthesized FePt nanoparticles: (a) M-H at 5, 50, 100, and 300 K with inset: expanded form of M-H at 300 K and (b) M-H at 5 K with insets: (i) its expanded view and (ii) variation of coercivity with temperature.
ZFC and FC curves for as-synthesized FePt nanoparticles at (a) different applied fields of 50, 100, 500, 1000 and 1 × 104 Oe and (b)50 Oe in expanded scale for clarity.
The real (a) and imaginary (b) parts of ac susceptibility for as-synthesized FePt nanoparticles measured at different ac frequencies and fixed amplitude of 4 Oe with no dc bias field. Inset: expanded form of the real part.
(a) Néel–Arrhenius model and (b) Vogel–Fulcher model fitting to the blocking temperatures obtained from the χ′ dataset peaks of as-synthesized sample.
The real (a) and imaginary (b) parts of ac susceptibility for FePt nanoparticles measured at varied dc bias fields and fixed ac field (amplitude = 4 Oe and frequency = 10 Hz). Arrow denotes the trend in positions of TB .
Hysteresis plot for the annealed sample: M-H at 5, 50, 100, and 300 K. Inset showing the expanded form with arrows indicating the kink.
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