Atomic layer deposition of ferromagnetic iron oxide films on three-dimensional substrates with tin oxide nanoparticles

Abstract

Magnetic iron oxide films were grown by atomic layer deposition. The films were grown from ferrocene and ozone precursors on planar and 3D SiO2/Si substrates. Some substrates were pre-covered with self-assembled SnO2 nanoparticles, prepared by hydrolysis of tin alkoxide with large excess of water. All samples demonstrated hysteresis in magnetization-field curves, defined and characterized on both planar and 3D substrates. The films on SnO2 possessed slightly higher coercivity and markedly higher saturation magnetization compared to the films on SiO2/Si. Both Fe2O3 and Fe3O4 were recognized in the as-deposited films without reducing Fe2O3 in H2. The application of SnO2 nanoparticles influenced the composition, also promoting growth and magnetization. The samples deposited at 350°C on 3D substrates with nanoparticles exhibited saturation magnetization of 0.0075emu/g, whereas in the samples without nanoparticles the magnetization remained at 0.0025emu/g. The highest coercivity of 425Oe was measured at room temperature in the film deposited at 400°C on planar substrate with SnO2 nanoparticles.