Holmium and titanium oxide nanolaminates by atomic layer deposition

•Ho2O3–TiO2 nanolaminates were grown by atomic layer deposition.•Ho2O3–TiO2 nanolaminates were crystallized at 700–800 deg.•Ternary Ho2Ti2O7 was formed upon annealing.•Annealed Ho2O3–TiO2 demonstrated soft magnetization hysteresis at room temperature.

Nanolaminate (nanomultilayer) thin films of TiO2 and Ho2O3 were grown on Si(001) substrates by atomic layer deposition at 300 °C from alkoxide and β-diketonate based metal precursors and ozone. Individual layer thicknesses were 2 nm for TiO2 and 4.5 nm for Ho2O3. As-deposited films were smooth and X-ray amorphous. After annealing at 800 °C and higher temperatures the nanolaminate structure was destroyed by solid-state reaction to form Ho2Ti2O7. The films demonstrated diamagnetic or paramagnetic behaviour in the as-deposited state. After annealing, the films possessed net magnetic moment, allowing one to record saturation magnetization and weak coercivity.