Thermal effects in self-assembled FePt nanoparticles with partial chemical ordering

Abstract

We have studied the thermal stability of self-assembled FePt nanoparticles with partial chemical ordering. The magnetic viscosity was measured at zero field after partial dc demagnetization as a function of the initial remanent magnetization. The viscosity curves are in good agreement with a calculation using a noninteracting Stoner–Wohlfarth, Arrhenius–Néel model with a broad distribution of anisotropy fields and randomly oriented easy axes. The shape of the zero field viscosity curve differs from curves measured for thin film media with in-plane and perpendicular anisotropy, in which interactions are known to be important.

Fabrication of L10 FePtAg nanoparticles and a study of the effect of Ag during the annealing process

“…FePtAg nanoparticles have been synthesized by the simultaneous polyol reduction of Pt (acac) 3 , Fe(acac) 2 and Ag. The addition of Ag to the FePt particles promoted the FCC phase transition to a tetragonal phase at a lower annealing temperature than that achieved with pure FePt nanoparticles.…”

“…The application of these FePt nanoparticles has focused primarily on their use in the next generation of ultra-high magnetic recording media [1][2][3][4][5][6][7].…”

Third-order elastic constants of the alloy Fe72Pt28

“…Because of the need for smaller grains, higher anisotropy materials are needed to maintain thermal stability. In order to optimise the recording performance, it is also important to have uniform grain size and weak inter-granular interactions [1]. IBM has recently reported the preparation of self-assembled super lattice films of iron platinum nano-particles with extremely uniform particle size [2].…”

Nanoparticles fabricated by selective reaction of Fe100−xPtx alloy films during imidization of polyamic acid

“…Although many different methods of synthesizing nanoparticles have been developed over the years, in order to consistently reproduce and utilize the size-dependent properties of these nanoparticles, particle size, size distribution, structure, and composition must be precisely controlled [1,2]. Many researchers have been successful in fabricating monodisperse metal and oxide particles in the size range of 1-20 nm, arranged in a regular superlattice [3][4][5]; however, the selfassembling process, largely relying on the weak van der Waals force of organic surfactants, is difficult to control. It is also questionable that the self-assembled system would be sufficiently robust for commercial applications.…”