After the observation of long-range magnetic order in two-dimensional (2D) magnets, the study of 2D magnetic heterostructures is the next step. The goal of this project related to the nucleation and manipulation of the spin textures, understanding the interfacial spin dynamics, and exchange bias at the bilayer interface of 2D magnet heterostructures. The Magneto-optical Kerr effect (MOKE) is our major technique to study the interfacial spin dynamics, exchange bias, and nucleation of spin textures at the surface and the interface of different heterostructures.

Innovating new spintronics and quantum computing applications requires the use of magnetic topological insulators (MTIs). MTIs provide strong electrical and magnetic characteristics against local perturbations under the topological protection given by the time-reversal Z2 invariant number. The quantum anomalous Hall effect (QAHE), which harbors dissipationless chiral edge states in MTIs, offers a competitive platform for the next high-speed and low-power spintronics devices. The goal of this study is to understand and manipulate the dynamical spin coupling as well as the carrier relaxation dynamics in MTIs, using static magneto-optical Kerr effect (MOKE) and time-resolved magneto-optical Kerr effect (TRMOKE) techniques.

A major challenge in the development of ultrafast spintronics is fast spin manipulation in magnetic heterostructures, where magnetic interactions between various materials frequently determine the performance of the devices. Spin angular momentum transfer in magnetic bilayers offers the possibility of ultrafast and low-loss operation for next-generation spintronic devices. This study is concerned with the analysis of the effective Gilbert damping and phase shift which indicates an enhanced dynamic exchange coupling between two ferromagnetic (FM) layers due to the reinforced spin pumping at resonance

These results provide valuable insight into the dynamic exchange coupling effect and the detection of the spin current.

The growing importance of ultrafast magnetoelectronics has triggered intensive research in magnetization and spin dynamics. The goal of this project is to elucidate the role of exchange bias, magnetic anisotropy, and interface magnetic structure on the ultrafast magnetization switching and damping mechanism in novel magnetic heterostructures.

Topics: Exchange Bias; Ultrafast Spin Exchange-Coupling Torque; Interface Magnetization Switching

The phase complexity in doped transition metal oxides makes the investigation of periodic layered structures especially intriguing, given the possibility of engineering charge, spin, and orbital ordering in a layer-by-layer manner. The goal of this project is to elucidate the interfacial magnetic structure and its correlation with charge transfer, orbital states, and strain states induced by the substrate in various complex oxide thin-film heterostructures and superlattices.

Topics: Magneto-Electric Effect; Interface Phenomena; Coherent Spin Dynamics; Coherent Acoustic Phonons

The goal of this project is to elucidate the dynamics of the local vibrational modes (LVMs) of defects related to light impurities in crystalline semiconductors (Si, Ge, GaAs) and metal oxides (ZnO, TiO2, KTaO3). This area of materials science is important to elucidate the degradation of electronic and optoelectronic devices and to advance solid oxide proton conductors for fuel cells, gas sensors, and proton-exchange membrane applications.

Topics: Proton Conducting Oxides; Defects in Semiconductors

The goal of this project is to study the relationship between vortex dynamics and ac losses in high-temperature superconductors. To achieve this objective we developed a new time-resolved magneto-optical imaging (TR-MOI) technique to study the interaction of an ac current with a magnetic field in nanoparticle-doped YBCO, multi-filamentary YBCO, and MgB2 thin films. Experimental technique.

Topics: Vortex Pinning; Magnetic Coupling

We are developing a terawatt Ti: Sapphire amplifier system capable of producing ultrashort laser pulses with energy up to 100 mJ and a duration of less than 100 femtoseconds at a 30 Hz repetition rate. The goal of this project is to use high-power laser pulses to generate short-pulse X-rays and to apply the fast X-rays in resonant X-ray magnetic scattering (RXMS) and X-ray magnetic circular dichroism (XMCD) studies of novel magnetic heterostructures.

Topics:Terawatt Laser Pulses, Nonlinear Magneto-Plasmonics; SP-Enhanced Transverse MSHG; Control of Magnetic contrast