Revealed: 3D magnetic configuration of ferrimagnetic multilayers with competing interactions

Researchers from the Physics Department of the Universidad de Oviedo, CINN-CSIC and HZB, in collaboration with ALBA, have explored the magnetic configuration of ferrimagnetic structures often employed to build modern spintronic devices and magnetic recording media. At the MISTRAL beamline of ALBA, using vector magnetic tomography, a magnetic trilayer fabricated at Oviedo was characterized. These findings will permit to generate precise physical models describing the magnetic behaviour of this type of systems and control and exploit them for the design of spintronics and magnetic storage devices.

 Modern spintronic devices and magnetic recording media often consist of complex magnetic structures. These structures are designed by precisely adjusting magnetic interactions as exchange, anisotropies and magnetostatics to achieve specific characteristics.

A collaboration between researchers from the Physics Department of the Universidad de Oviedo, the Centro de Investigación en Nanomateriales y Nanotecnología (Oviedo), the Helmholtz Zentrum Berlin für Materialien und Energie (Berlin) and the ALBA Synchrotron have investigated a combination of ferrimagnetic structures, often employed to build this type of devices. 

At the MISTRAL beamline of ALBA, a dichroic vector magnetic tomography of the device was performed and it revealed details of complex magnetisation configurations of the sample. The importance of synchrotron light lies in the fact that this information is currently impossible to evidence with other techniques when studying magnetic thin films.

The ability to characterize the configuration of the magnetisation in complex structures with competing magnetic interactions will permit to generate precise physical models describing the magnetic behaviour of these systems. Thus, experts will be able to control and exploit them for the design of spintronics and magnetic storage devices.

Read more on the ALBA website

Image: Magnetisation obtained from the magnetic tomography data at the MISTRAL beamline.

Green information technologies: Superconductivity meets Spintronics

Superconducting coupling between two regions separated by a one micron wide ferromagnetic compound has been proved by an international team. This macroscopic quantum effect, known as Josephson effect, generates an electrical current within the ferromagnetic compound made of superconducting Cooper-pairs. Magnetic imaging of the ferromagnetic region at BESSY II has contributed to demonstrate that the spin of the electrons forming the Cooper pairs are equal. These results pave the way for low-power consumption superconducting spintronic-applications where spin-polarized currents can be protected by quantum coherence.

When two superconducting regions are separated by a strip of non-superconducting material, a special quantum effect can occur, coupling both regions: The Josephson effect. If the spacer material is a half-metal ferromagnet novel implications for spintronic applications arise. An international team has now for the first time designed a material system that exhibits an unusually long-range Josephson effect: Here, regions of superconducting YBa2Cu3O7 are separated by a region of half-metallic, ferromagnetic manganite (La2/3Sr1/3MnO3) one micron wide.

Read more on the HZB website

Image: Device where the long range Josephson coupling has been demonstrated.  Superconducting YBa2Cu3Oregions (yellow) are separated by a half-metal La2/3Sr1/3MnO3 ferromagnet (green).

Credit: © Nature Materials 2021: 10.1038/s41563-021-01162-5

Spintronics: Exotic ferromagnetic order in two-dimensions

An international team has detected at HZB’s vector magnet facility VEKMAG an unusual ferromagnetic property in a two-dimensional system, known as “easy-plane anisotropy”. This could foster new energy efficient information technologies based on spintronics for data storage, among other things. The team has published its results in the renowned journal Science.

The thinnest materials in the world are only a single atom thick. These kinds of two-dimensional or 2D materials – such as graphene, well-known as consisting of a single layer of carbon atoms – are causing a great deal of excitement among research teams worldwide. This is because these materials promise unusual properties that cannot be obtained using three-dimensional materials. As a result, 2D materials are opening the door to new applications in fields such as information and display technology, as well as for critical components in extremely sensitive sensors.

Read more on the HZB website

Image: STM topography of a monolayer CrCl3 grown on Graphene/6H-SiC(0001). Inset, a magnified topography image, which reveals the grain boundaries.

Credit: HZB