Magnetism of FePt Nanoclusters in Polyimide

الملخص EN

FePt nanoclusters have been implanted onto polyimide films and subjected to thermal annealing in order to obtain a special magnetic phase (L10) dispersed within the polymer.

SQUID measurements quantified the magnetic features of the as-prepared and annealed hybrid films.

As-implanted FePt nanoparticles in polyimide films exhibited a blocking temperature of 70 ± 5 K.

Thermal annealing in zero and 10 kOe applied magnetic field increased the magnetic anisotropy and coercivity of the samples.

Wide Angle X-Ray Scattering confirmed the presence of FePt and L10 phase.

All samples (as deposited and annealed) exhibited electron spin resonance spectra consisting of two overlapping lines.

The broad line was a ferromagnetic resonance originating from FePt nanoparticles.

Its angular dependence indicated the magnetic anisotropy of FePt nanoparticles.

SEM micrographs suggest a negligible coalescence of FePt nanoparticles, supporting that the enhancement of the magnetic properties is a consequence of the improvement of the L10 structure.

The narrow ESR line was assigned to nonmagnetic (paramagnetic) impurities within the samples consistent with graphite-like structures generated by the local degradation of the polymer during implantation and annealing.

Raman spectroscopy confirmed the formation of graphitic structures in annealed KHN and in KHN-FePt.