Optimization of DyFe nanostructures using E-beam lithography for magneto-optical applications

Low dimensional artificially engineered spintronic materials can be used to increase the density of magnetic media using energy based magnetic recording. For this purpose, magnetic nanostructures such as patterned arrays with magnetic characteristics having high uniaxial magnetic anisotropy are the new contestants in the field of ultrahigh storage media. In this context, we focus on the synthesis of nano-dimensional magnetic media consisting of Dy and Fe bilayer structured arrays, fashioned in patterned magnetic nanostructures. The dimensional characteristics of these nanostructures were illustrated using field emission electron microscopy and energy dispersive elemental mapping. Room temperature magnetic properties of these nanostructures were first determined through atomistic spin model simulations which led us to configure the experimental hysteresis loop for DyFe bilayer. The deposition of crystalline Dy and Fe through DC and RF sputtering resulted in a soft magnetic behavior as revealed by the characteristic shape of the hysteresis loops exhibiting anisotropic features. Reflection spectra for these DyFe bilayers reveal a decrease in reflectance from ultraviolet to visible region demonstrating high absorption in visible region. The variation in reflectance spectra and squareness of the hysteresis loop reveals that these nanostructures as a viable candidate for magneto-optical devices.