Session 2B: Inaugural Lectures by Fellows/Associates

Anil K. Gupta, IIT Kharagpur

Spin texture driven magnetization dynamics in engineered magnetic nanostructures

Engineered magnetic nanostructures will form important building blocks for next-generation spintronics and externally controlled spin textures offer new opportunities for novel spin-based device fabrication. The optimization of these devices demands understanding and control of ultrafast spin dynamics as well as spin-wave propagation. Here, femtosecond laser-induced ultrafast magnetization dynamics controlled by domain-wall origami in a [Co/Pt]22 multilayer will be discussed. Depending on the underlying domain landscape, the spin-transport-driven magnetization dynamics show a transition from ultrafast demagnetization to an anomalous transient magnetization enhancement (TME) via a state where both TME and demagnetization coexist in the system. Thereby, the study revealed an extrinsic channel for the modulation of spin transport, which will introduce a route for the development of magnetic spin-texture-driven ultrafast spintronics devices. Furthermore, the development of on-demand magnonic nanochannels by periodically tailoring perpendicular magnetic anisotropy using an electric field will be discussed. Brillouin light scattering measurement revealed magnonic bands, consisting of two spin-wave frequency modes, along with a bandgap under the application of moderate gate voltage, which can be switched off by withdrawing the voltage. The anticrossing between these two modes gives rise to the observed magnonic bandgap. This study will lead to on-chip parallel data communication and processing.