We present a study of a facile technology for establishing mono- and multilayer nanostructures made from single-domain flat magnetic nanoparticles. These nanoparticles exhibit a strong, perpendicular-oriented magnetic moment on solid and flexible substrates. Surfactant-free, hard ferromagnetic, and single-domain anisotropic strontium hexaferrite SrFe12O19 nanoparticles with perpendicular magnetic moment orientation and two different aspect ratios are self-ordered into magnetic thin nanofilms exploiting the templating effect of cellulose nanofibrils, spray deposition, and magnetic fields. Uniform magnetic coatings obtained by scalable layer-by-layer spray deposition from a monolayer coverage up to thicknesses of a few tens of nanometers show the preferred in-plane orientation of the hard-magnetic nanoparticles. Using grazing incidence X-ray scattering, we quantify the self-assembly during spray-deposition and the nanoparticle stacking into three-dimensional multilayer structures. Application of the magnetic field during film deposition ensures additional improvement in perpendicular magnetic anisotropy and the appearance of residual magnetization in the film of up to 0.6MS. For low aspect ratio nanoparticles stacked periodic planar structures, the signs of the photonic band gap are revealed. The ability to create scalable, thin magnetic structures based on nanosized particles/building blocks opens great opportunities for their application in a wide variety of optoelectronic and magnetic storage devices.

Sprayed nanometer-thick hard magnetic coatings with strong perpendicular anisotropy for data-storage applications

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ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.