Thin magnetic films of Sm–Co nanocrystallites exploiting spin coating deposition

Thin magnetic films of Sm–Co nanocrystallites on SiO2 substrate were fabricated using spin coating deposition. In a typical synthesis, precursor of Sm–Co oleate complex was spin coated onto a SiO2 substrate in the form of precursor films and subsequently they were subjected to reductive annealing at 773 K for 2 h, so as to crystallize Sm–Co phase in the films. It has been found that the reductive annealing temperature (573–773 K) played a critical role on the nucleation and formation of Sm–Co crystalline phases; while the spinning speed (3000–5000 rpm) has a significant effect in controlling the film thickness, which in turn affects the particle diameter, inter-particle distance and packing density of the Sm–Co nanocrystallites. Coercivity values of 27.9, 23.9 and 18.7 kA⋅m− 1 and magnetization values of 2.89, 2.51 and 2.21 × 10− 6 A⋅m2 were achieved for the Sm–Co films with thicknesses of 345 (3000 rpm), 264 (4000 rpm) and 162 nm (5000 rpm), respectively. Further, these hard magnetic properties could be significantly improved by subjecting the Sm–Co films to post-annealing at 873 K.