Exploring Magnetic Properties of Nanocap Thin Films Fabricated with Dry-Rubbed Nano/Microsphere Templates

Various nanostructures can be fabricated using hexagonally close-packed single-layer nano/microsphere templates. Thin magnetic layers on such templates result in curved nanomagnetic thin films. This induced curvature creates unique magnetic domains with potential applications in data storage devices, spintronics, and chemical sensors. This study employs a manual rubbing method using a polydimethylsiloxane (PDMS) stamp to quickly achieve hexagonally close-packed single layer template. Nanocap structures of Permalloy or Samarium Cobalt were made on top of template by sputtering deposition. Spheres with various types of materials and diameters ranging from 800 nm to 10 µm were used. Spheres of 800 nm polystyrene, 10 µm silica, and 1, 3, and 5 µm Poly methyl methacrylate were deposited on silicon substrate. Optical microscope and scanning electron microscope images show that each template achieved extensive substrate coverage, although notable stacking issues were observed in some templates. When the same PDMS stamp was reused to make another template, the stacking issue was partially resolved. Magnetic hysteresis loop measured by Magneto Optical Kerr Effect resulted in different magnetic switching behaviors depending on the microstructures of thin films.