Collectively we have over 18 years experience in materials modelling, working at the highest level with companies such as Seagate, and Toyota on magnetic material development for example. Our work has spanned across solid state materials and many of the different disciplines that involves.
One of Prof Hrkac's main research areas, sponsored by the Royal Society, is magnetic spintronics where he studies spin transfer effects of spin-polarized current in magnetic nanoscale devices. Such a polarized current can either switch or induce sustained precessional modes at a microwave frequency in a magnetic multi layer stack. These effects can be used in magnetic memory devices or in new types of microwave oscillators e.g. spin transfer nano oscillators STNO. Starting from his early work on spin current induced magnetic vortex oscillators, first theoretical and experimental proof of a vortex induced oscillation in a nano-contact device (PRL 100 2008), together with Prof Chappert’s group at Univesite Paris Sud, he developed a multi-scale model approach where he combined a spin diffusion equation in 3D (metal and ferro-magnet Weak formulation) and coupled this to the magnetization dynamics equation described by the Landau-Lifshitz-Gilbert equation. In this approach the charge/spin currents are calculated by solving the spin diffusion equation simultaneously with the LLG equation by using a weak formulation discretized in space by the finite element method.
This multi-scale model was used in the investigation of magnetic hybrid structures in collaboration with Prof Heyderman, PSI and ETH,and Prof Thomson Manchester University. In this joint project they clarified with simulations that the complex imprinting pattern encountered in CoPd/NiFe hybrid structures can be used to trap magnetic vortices in the NiFe layer via perpendicular imprinted domain structures originating from the CoPd layer. Furthermore, they first predicted theoretically and then found experimentally that by driving the vortex over an imprinted domain structure you can change the polarity of the vortex via a new type of “Bloch core” reversal mechanism. This effect can be used for advanced magnetic-logic and oscillation devices and was published in Nature Communications, Physical Review B and Applied Physics Letters.
