Structural and magnetic properties of monolayer film of CoPt nanoparticles synthesized by polyol process

Abstract

Co 43 Pt 57 nanoparticle dispersion was synthesized by using the polyol process, and monolayer film of the particles with [3-(2-aminoethylamino)propyl]trimethoxysilane coupling layer on a silicon substrate was fabricated and characterized. After the film was annealed at 873K, the Co43Pt57 nanoparticles transformed from their as-deposited fcc phase to L10 structure. However, the resulting c∕a ratio was only 0.993, indicating incomplete transformation. Grain size of the annealed film was 4.9nm against 4.1nm for the as-deposited state. The annealed film showed the presence of high anisotropic phase with the remanence coercivity of 4.2kOe and anisotropy field over 25kOe at RT.