Research Topics

Multiscale Modelling in Magnets:
The magnetization dynamics are described by the traditional Landau-Lifshitz-Gilbert (LLG) equation that consists of the precession of magnetic moment around an effective field and dissipation of energy in terms of Gilbert damping. To model the magnetization dynamics the LLG equation is solved with the effective field that is already present in a system. The effective field is calculated from the total ground state energy of a magnetic system. Such energy includes magnetic exchange, anisotropy, and other types of energy contributions that can be calculated within a density functional theory (DFT) approach. The multiscale modeling in magnets provides important ground state characteristics. 

Reference:  Schmidt, Mondal et. al. Phys. Rev. B 102, 214436 (2020)

Antiferromagnetic spintronics:
Antiferromagnets consist of two opposite spins with equal magnitude. The exchange energies between these two spins are very strong. The antiferromagnets show faster dynamics than ferromagnets due to their natural THz resonance frequency. The antiferromagnets are abundant in the world and they do not possess any stray fields. Owing to these fundamental properties, the antiferromagnetic spins can be densely packed in a small magnetic domain and they are robust against external perturbation which makes antiferromagnets a perfect material for data storage devices. The switching of antiferromagnets shows 90 degrees that cost less energy than 180 degrees switching.    

Ref: Mondal et. al. Phys. Rev. B 100, 060409 (2019)

Ultrafast Spin Dynamics:
The pioneering work of femsotsecond control of magnetism in Ni was discovered in 1996 which showed the spins can be manipulated at ultrafast timescales. Such remarkable achievement has changed the technological solutions of data storage devices. Not only the ultrafast demagnetization, but also, the thermal switching in ferrimagnets can be explained by the solutions of the LLG equations having two sublattices with the laser heating included. Apart from the traditional LLG spin torques, there could be several other spin torques e.g., spin-transfer torque, spin-orbit torque, optical spin-orbit torque, and others contributing to the LLG spin dynamics.  The effects of these torques need to be investigated for several classes of magnets.

Reference: Mondal et. al. Phys. Rev. B 98, 214429 (2018)