Osaka University, Japan, has improved an ultra-thin film of magnetite, a black oxide class mineral used in electronics.

It was made on a crystal surface, treated with an original high-precision polishing technology and got a perfect surface. By reducing the number of defects on the substrate, scientists have achieved the excellent transient properties inherent in magnetite. Previously, it was difficult to do precisely because of the imperfection of the top layer of the film.

“The uniformity and properties of thin films are dependent on the perfection of the substrate,” explains lead author Ai Osaka. “Traditional monocrystalline substrate preparation technologies sacrifice crystallinity for plane optimization, but this limits film performance.”

The researchers used the chemical polishing technique (CARE) to prepare an atomically flat magnesium oxide substrate. Magnetite on an ultra-smooth substrate has superior crystallinity and conductive properties compared to magnetite deposited on a conventional substrate.

Scientists are investigating the magnetic and conductive properties of thin films of magnetite, because it is a material with theoretically predicted one hundred percent spin polarization of electrons. It is needed for electronic devices that use pure spin current, a more efficient analogue of electric current.

These results are important for the development of quantum computing.