Self-assembly epitaxial lithium ferrite nanostructures with tunable magnetic properties

High-performance ordered arrays of nanostructure has attracted significant attention due to the needs for miniaturization in electronic and spintronic devices. However, the traditional templete-assisted method often entails expensive equipment and complicated processing. Herein, a series of high quality LiFe₅O₈ (LFO) arrays are obtained by chemically etching the MgO phase in the self-assembly (LFO)₁:(MgO)_x nanocomposite films. The LFO arrays show excellent epitaxial quality and nano-island or nano-pillar morphology, which can be easily fabricated by controlling the thickness and chemical component of the grown nanocomposite films. In comparison with the LFO planar film, the LFO nanopillar arrays exhibit higher saturation magnetization, lower non-zero coercivity and remanence. Moreover, the morphology of the nanostructures can effectively modulate the ferromagnetic resonance spectra of the LFO nanopillar arrays, which can be explained by the calculated demagnetization field. This work shows that nanostructure engineering is very useful to modulate the magnetic properties and to design compact microwave magnetism devices.