Self-assembling epitaxial growth of a single crystalline CoFe2O4 nanopillar array via dual-target pulsed laser deposition

Abstract

Magnetic nanopillars are promising for a variety of technological applications, though the template-free fabrication of magnetic nanopillar arrays with good crystallinity and uniform distribution remains a substantial challenge. Herein, we report successful fabrication of a regular array of CoFe₂O₄ (CFO) nanopillars using an elaborately designed dual-target pulsed laser deposition (PLD) process, which exhibit a truncated pyramid surface with consistent size and orientation as well as uniform distribution. Detailed X-ray diffraction, scanning transmission electron microscopy and X-ray photoelectron spectroscopy demonstrate the high quality nature of the CFO nanopillars, while vibrating sample magnetometer and magnetic force microscopy studies confirm their room temperature magnetism. This dual-target PLD process takes advantage of BiFeO₃ decomposition, and the subsequent formation of CFO nanopillars requires no template, giving us a powerful technique to prepare oxide nanopillars with desired composition and functional properties.