UrFU Scientists Produce Cheap Nanostructural Film

10:39, November 19, 2020

This technology in principle was first published in an article 'Antidot patterned single and bilayer thin films based on ferrimagnetic Tb–Co alloy with perpendicular magnetic anisotropy' back in 2018

The creation of an ordered array of nanoscale holes of the same size over a large area is a difficult and costly task if solved directly by creating holes in a continuous film. Dr. Nikita Kulesh from the Ural Federal University took a different, less expensive path and suggested using the effect of self-assembly or self-organization.

This effect consists in the application of aluminum anodizing technology to obtain porous surfaces with a slight modification, allowing to obtain holes with a well-controlled diameter, arranged in a hexagonal lattice. The anodized aluminum layer consists of a very hard material with the chemical formula Al2O3, which in its crystalline state is known as corundum or sapphire. As a result of the process of self-organization of pores, a surface is obtained that resembles a honeycomb, reduced by about a million times. An aluminum substrate with regularized pores was developed a quarter of a century ago. In recent years, it has been used as a basis for applying films, including magnetic ones, and as a template for growing metal nanowires.

Physicists of Ural Federal University, together with researchers from the Institute of Materials Science of Madrid (Spain), using a well-known method, obtained a unique amorphous TbCo film with perpendicular magnetic anisotropy. The results of the work are presented in the journal Nanotechnology.

"This material is unusual in that it contains two magnetic sublattices, the magnetic moments of which are directed in opposite directions. For certain compositions of the film, when it is heated or cooled, its magnetic properties will change significantly. This property can be especially useful when creating media for magnetic recording of information ", - said Nikita Kulesh, senior researcher at the Department of Solid State Magnetism, UrFU.

Magnetic film with nanosized holes is interesting in that it allows you to overcome the so-called superparamagnetic limit - when the size of a bit becomes so small that the energy of thermal vibrations begins to prevail over the energy of magnetic anisotropy, scientists said.

At the moment, UrFU has implemented a full cycle of creating nano-perforated film samples of different coating compositions. This includes the electrochemical synthesis of porous anodized aluminum substrates with different hole diameters or an array of nanoscale bulges, deposition of film coatings with precise control of composition and thickness, and equipment for studying the obtained samples.star_border