High coercivity FePt/CNT nanocomposites on SiO2 surface

The growth of 2 nm FePt nanocrystals on the wall of functionalized carbon nanotubes provides the ability of their size control under heat treatment for transformation to L10 phase. FePt/CNTs nanocomposites are coated on SiO2 wafers in presence of 0.5 T magnetic field and post annealed under reducing atmosphere (10% H2, 90% Ar) at 700 °C and different annealing times. The best result is recorded for 3 h annealing time at 700 °C. In this condition, the coercivity and chemical ordering of FePt/CNT nanocomposites are raised to 0.85 T and 99% respectively, even though FePt particles have the average size of about 5 nm.