Thin films of oriented tetragonal FePt particles separated by amorphous alumina have been fabricated by electron beam evaporation. The ordering of the FePt particles without coarsening can be tailored by annealing conditions. The value of coercivity of the annealed film reached as high as 4.4 kOe. The perpendicular magnetic coercivity of the annealed film was slightly larger than in-plane coerc...

Synthesis of FePt nanoparticles with controlled shape and magnetic alignment has become an important goal in developing nanocrystal arrays for applications in information storage, permanent-magnet nanocomposites, and catalysis. FePt alloys are chemically stable owing to the spin–orbit coupling and the hybridization between Fe 3d and Pt 5d states, and their magnetic properties can be tuned by si...

Magnetic layers and layered structures with defined physical properties are of high interest for magnetoelectronic and magnetoelectromechanical applications as well as for magnetic data storage. New deposition technologies become more important in industrial branches for magnetic applications. Electrochemical deposition methods are favoured due to their low costs compared to physical deposition...

Magnetic (FePt) and nonmagnetic (Au) nanoparticles were used to assemble ferritin into near-monodisperse bionanocomposites featuring regular interparticle spacing. The FePt/ferritin assemblies are integrated magnetic materials with ferritin providing added magnetic volume fraction to the magnetic nanocomposite. These assemblies differ from either of their constituent particles in terms of block...

Large-scale first principles calculations for near-stoichiometric FePt and CoPt clusters with up to 923 atoms are presented including unconstrained structural relaxations. The energetic order and magnetic properties of 561 atom FePt and CoPt nanoparticles are evaluated with emphasis on segregated morphologies with Pt covered surfaces. The results imply that for CoPt particles segregation of Pt ...

Fully ordered face-centered tetragonal (fct) FePt nanoparticles (NPs) are synthesized by thermal annealing of the MgO-coated dumbbell-like FePt-Fe3O4 NPs followed by acid washing to remove MgO. These fct-FePt NPs show strong ferromagnetism with room temperature coercivity reaching 33 kOe. They serve as a robust electrocatalyst for the oxygen reduction reaction (ORR) in 0.1 M HClO4 and hydrogen ...

Abstract To realize high areal density, hard disk drives larger than 4 Tbit in −2 , ultrafine FePt grains of less 5 nm and grain density 24 T are required. Although there have been many investigations to reduce the size FePt, only a few reports on control density. increase we focused three aspects surface morphology density: nucleation sites substrate surface, free energy, lattice mismatch. We ...

Chemically ordered, self-assembled FePt nanoparticle arrays with high magnetic anisotropy are considered a candidate medium for data storage beyond 1 Tbit/in. We report comprehensive structural and magnetic studies on thin (3 layer) assemblies of polyethylenimine (PEI) and 4 nm Fe58Pt42 nanoparticles using X-ray diffraction, small angle neutron scattering and magnetometry. We show that prior to...

Monodisperse face-centred tetragonal (fct) FePt nanoparticles with high magnetic anisotropy and, therefore, high coercivity have been prepared via a new heat treatment route. The as-synthesized face-centred cubic FePt nanoparticles were mixed with salt powders and annealed at 700 ̊C. The salts were then removed from the particles by washing the samples in water. Monodisperse fct FePt particles w...

A pre-annealing atmospheric pulsed laser exposure was applied to decrease the phase transition (from chemically disordered A1 phase to chemically ordered L10 phase) temperature of FePt nano-particles on a Si (100) substrate. Different pre-annealing laser energy densities of 0.024 and 0.079 J/cm were utilized to expose the pulsed laser deposition (PLD) FePt thin film samples under atmospheric co...