Towards the on-demand voltage control of antiferromagnetic domains

• Applicant: Somnath Ghara, Ph.D.
• Subject Area: Experimental Condensed Matter Physics
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 532417292

In the present era of information technology, it is of an urgent need to miniaturize and speed-up the technological devices. This requires conceptually novel ideas and revolutionary approaches and relies on the development of new active elements. In the traditional spintronic devices ferromagnets are the most common material platform. However, their stray fields, slow spin dynamics and high sensitivity to external fields make them inappropriate for the next generation devices. In the recently emerging field of antiferromagnetic spintronics, the antiferromagnets have been realized as potential alternative candidates due their unique properties, which are not restricted by these limitations. Noncentrosymmetric antiferromagnetic metals, where electric current can manipulate antiferromagnetic states via spin-orbit torque, have already gained attention, however, the joule heating caused by the electric current limits their applications. In this context, the noncentrosymmetric antiferromagnetic insulators may act as alternative platforms, where the antiferromagnetic states can be controlled by electric field governed by the magnetoelectric coupling in a dissipation-less manner. Despite the recent progress in antiferromagnetic spintronics, the on-demand electric control of antiferromagnetic states is still a great challenge, especially with high-speed operation, and leaves a number of fundamental questions unanswered. In this proposal, via performing a detailed magnetoelectric measurements on the bulk crystals and microstructures of a promising antiferromagnetic insulator, Co3O4, we plan to address the long-standing question of how fast the antiferromagnetic domains can be switched by voltage pulses. In order to explore further possible paths for the manipulation of antiferromagnetic domains, the quantification of their population and the direct visualization of their nucleation and switching process is also of high priority. There are various novel techniques capable of imaging antiferromagnetic domains, however, these are not universally applicable to all antiferromagnets. Via utilizing two different imaging techniques on the same template material we will address on their suitability on the visualization of antiferromagnetic domains and their transformations under magnetic and electric fields. These proposed studies, being at the frontier of magnetism, materials science and spintronics, will help in further exploring and understanding the physics of antiferromagnets and may pave the way for fast-operation magnetoelectric-antiferromagnetic devices.

• DFG Programme: Research Grants