Surface plasmons (SPs) introduce large enhancement of the local field intensity by coupling incident photons to conduction electrons of metals. The goal of this project is to utilize the local field enhancement induced by the excitation of surface plasmons to optically control and modulate the magnetism in novel magneto-plasmonic nanostructures. Magneto-optical Kerr effect (MOKE) and magnetization-induced second harmonic generation (MSHG) are our major techniques to detect the plasmon-induced magnetic anisotropy changes at surface and interface.

Topics: Nonlinear Magneto-Plasmonics; SP-Enhanced Transverse MSHG; Control of Magnetic Contrast

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 the 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 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 duration of less than 100 femtosecond at 30 Hz repetition rate. The goal of this project is to use the 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