Fabrication of isolated CoGdTb magnetic nanodots with perpendicular magnetic anisotropy

The authors report that a closely-packed hybrid nanostructure can be fabricated by using simple sputtering deposition and anodized aluminum oxide (AAO) templates. In order to isolate CoGdTb magnetic materials with the AAO template, carbon nanotubes (CNTs) were incorporated into the AAO template. Scanning electron microscopy reveals that the nanodots are formed exactly on the top of CNTs, which are placed in a regular arrangement over a wide range area. This indicates that magnetic nanodots, well-arranged over a large area, can be formed using simple sputtering deposition. Isothermal magnetization shows that the CoGdTb nanodots have perpendicular magnetic anisotropy and the strength of the dipolar interaction between the magnetic nanodots can be also controlled by adjusting the spacing between the dots.