Scientists in their latest study claims to have found a way to control the alignment state of magnetic atoms in an anti-ferromagnetic material. It looks promising for the development of better smaller sensors and storage devices. The researchers now describe their new approach consisting of a controllable exchange bias effect which enables asymmetrical magnetic actions of devices that consist of a complex combination structure of different types of magnetic materials.
Spintronics is an emerging technology for making electronic devices that use the electron's spin and the related magnetic properties, rather than just using the electrical charge of an electron to transfer information. Antiferromagnetic materials has catch the attention of researchers in spintronics, with the expecting spin operations with increased stability. In contrast to ferromagnetic materials, whose atoms are aligned in the same direction as in typical refrigerator magnets, the magnetic atoms in an anti-ferromagnets have antiparallel spin orientations that cancels out its net magnetization.
Scientists have worked out to control the orientation of magnetic atoms in antiferromagnetic materials to create magnetic switches. Traditionally, this has been done using a "field cooling" technique in which a magnetic system that contains an anti-ferromagnetic material is heated and then cooled simultaneously while an external magnetic magnet is applied. However, this process is ineffective for use in many micro- or nanostructured spintronic devices because the spatial resolution of the process itself is not high enough to be applied in micro- or nanoscale magnetic field, says Jung-Il Hong from Spin- DGIST Nanotechnology Laboratory. The process can replace conventional heating and cooling, which is inconvenient and harmful to magnetic material. “We hope that our new process will enable the integration of antiferromagnetic materials into spintronics-based micro and nano devices”, says Jung-II Hong.
Hong and his colleagues combined two layers: a ferromagnetic cobalt-iron-boron film over an antiferromagnetic iridium-manganese film. The layers were grown on piezoelectric ceramic substrates. The combined application of mechanical vibration and a magnetic field enabled the scientists to repeatedly control the orientation of the magnetic spins in any desired direction. The team has set itself the goal of continuing the research and development of new magnetic phases beyond conventionally classified magnetic materials. "In the past, the discovery of new materials has led to the development of new technologies, says Hong. This research work will be the seed for new technologies.