报告时间：2018年8月16日 周四 下午15:30~17:30
邀 请 人：陶文铨教授 唐桂华教授
报告1题目：Study of Thermal Transport in Micro/Nanostructured Materials and across Interfaces Enabled by Ultrafast Pump-Probe Techniques
报告1摘要：Transport phenomena play an important role in designing and engineering materials with tailored functionalities. Accordingly, the transport properties of materials can provide a wealth of information on the fundamental scattering processes of charge, heat, and spin carriers with structural defects, boundaries, and interface imperfections. For the first talk, I will start with the introduction to the fundamental concepts of micro/nanoscale heat transfer, followed by several examples of utilizing the state-of-the-art ultrafast pump-probe techniques to study the thermal properties of nanomaterials spanning a wide range. This will include but not be limited to: (1) revealing the origins of the 3D anisotropic thermal transport in black phosphorus, which is the next-generation of “wonder materials” for the semiconducting industry; (2) creating ultralow thermal conductivity using single crystals of correlated perovskite oxides; (3) engineering the interfacial thermal transport across solid-solid (sapphire and polystyrene) interfaces by adding self-assembled monolayer (SAM, saline groups); (4) tailoring the interfacial thermal transport across solid-liquid (nanoparticles and water) interfaces by functionalizing the solid with hydrophobic and hydrophilic surfactants; and (5) tuning the thermal performance of nanocomposites, which serve as thermal interface materials for effective heat dissipation.
报告2题目：Ultrafast Magnetization Dynamics in Perpendicular Magnetic Materials
报告2摘要：In the second talk, I will focus on the advanced Time-Resolved Magneto-Optical Kerr Effect (TR-MOKE) metrology for studying the magnetization dynamics of materials. With optical excitation and the capability of reaching large magnetic fields, TR-MOKE can probe spin precession at high resonance frequencies (up to a few hundreds of GHz), beyond those achievable by conventional Ferromagnetic Resonance (FMR) methods. I will demonstrate the use of TR-MOKE to study the spin precession of tungsten (W)-seeded CoFeB thin films with large perpendicular magnetic anisotropy (PMA), which serve as promising building blocks for spintronic devices.
Dr. Xiaojia Wang started her official appointment as an assistant professor in the Department of Mechanical Engineering at the University of Minnesota, Twin Cities in 2014. Prior to this, she was a postdoctoral research associate in the Department of Materials Science and Engineering at the University of Illinois at Urbana-Champaign. She received her Ph.D. in Mechanical Engineering from the Georgia Institute of Technology in 2011, and her M.S. in 2007 and B.S. in 2004 from Xi'an Jiaotong University, China, all in Mechanical Engineering. Her current research focuses on (1) utilizing ultrafast optical techniques to characterize thermal and magnetic transport in micro/nanostructured materials and across material interfaces; and (2) tailoring the radiative properties of micro/nanostructures for energy conversion and harvesting. For details, please visit her research group website: http://www.me.umn.edu/labs/mnttl/.