Research Projects

The research in spintronics aims to advance the present memory and computation technology by engaging the spin degree of electron. The use of femtosecond optical pulses is relevant, which has shown to trigger the fastest changes in the magnetic state of matter, leading to the possibility of high speed and energy efficient opto-spintronic memory. In the past decade, the prospects of ultrafast optomagnetic control in different materials were explored, leading to the exploration of optically generated spin current as well as spurring interest in the fundamental understanding of light– spin interaction on ultrashort timescale. In the literature, relaxation of spin angular momentum through ultrafast spin polarized hot electron transport post optical excitation have been proposed. Overall, the transition of spin during this process is intricately linked to the band structure and magnetic coupling, and a control on them can lead to ultrafast optical spin switching on demand. With the advent of new classes of advanced materials such as 2d materials, antiferromagnetically coupled systems etc., the idea of ultrafast optical control of spin currents and spin-polarized electrical currents appears to be very promising. These new age materials offer unique band structures, providing new ultrafast spin transfer pathways. For example, in topological insulators, the surface electron states are spin polarized. Such optically excited surface currents can exert spin-transfer torque effects in adjacent ferromagnetic layers, being the size of the torque greater than the one induced by any other material so far. Such torque is capable of switching the magnet on ultrafast timescale. On the other hand, the transient intersublattice interaction after optical stimulation in antiferromagnets provides unique scope of magnetic switching through intersublattice spin exchange. As antiferromagnets are insensitive to external perturbation as well as exhibit terahertz dynamics, they have huge potential for ultrafast opto-magnetic memory and switches. In this proposal, I aim to build an ultrafast magneto optical pump probe spectroscopy and imaging setup to explore the prospects of optical control of magnetization and investigate the underlying spin dynamics in different state of the art materials. In the initial phase, designing and fabrication of magnetic nanostructures as well as building of the time resolved spectroscopy will take place. Subsequently, I will study the response of the magnetization to femtosecond optical pulses and investigate the dynamics on sub-picosecond timescale. Overall, although future research efforts are highly required, the emergence of all optical manipulation of magnetization as a successor of heat assisted recording technology opens a plethora of opportunities at the intersection of photonics and spintronics.