Selective growth of pure magnetite thin films and/or nanowires grown in situ at a low temperature by pulsed laser deposition

Abstract

Pure Fe₃O₄ thin films and/or nanowires were selectively grown onto c-Al₂O₃ (0001) substrates in situ at different substrate temperatures using pulsed laser deposition (PLD). The epitaxial Fe₃O₄ thin films were grown at deposition temperatures that ranged from 300 to 600 °C, while nanowires with a single-crystalline nature were grown at temperatures of more than 600 °C without catalysts. The in-plane compressive stress of the films increased as deposition temperature increased. Protrusions to relieve the compressive stress typically formed at the low-angle grain boundaries and were then developed to make nanowires. Both the films and the nanowires showed a ferromagnetic nature and a magnetic anisotropy at room temperature.