Memory Effects in Nanolaminates of Hafnium and Iron Oxide Films Structured by Atomic Layer Deposition.

HfO 2 and Fe 2 O 3 thin films and laminated stacks were grown by atomic layer deposition at 350 °C from hafnium tetrachloride, ferrocene, and ozone. Nonlinear, saturating, and hysteretic magnetization was recorded in the films. Magnetization was expectedly dominated by increasing the content of Fe 2 O 3 . However, coercive force could also be enhanced by the choice of appropriate ratios of HfO 2 and Fe 2 O 3 in nanolaminated structures. Saturation magnetization was observed in the measurement temperature range of 5-350 K, decreasing towards higher temperatures and increasing with the films' thicknesses and crystal growth. Coercive force tended to increase with a decrease in the thickness of crystallized layers. The films containing insulating HfO 2 layers grown alternately with magnetic Fe 2 O 3 exhibited abilities to both switch resistively and magnetize at room temperature. Resistive switching was unipolar in all the oxides mounted between Ti and TiN electrodes.