邀请讲座人：王小佳  副教授

报告题目：Capturing and Manipulating Magnetization Dynamics in PMA Materials for Spintronic Applications

讲座时间：2023年5月26日 14:30

讲座地点：材料学院仲英楼第一会议室（A245-247）

报告摘要：In this talk, I will highlight our group activities in exploring the magnetization dynamics of materials with perpendicular magnetic anisotropy (PMA) using the ultrafast laser-based time-resolved magneto-optical Kerr effect (TR-MOKE) metrology. With optical excitation and detection, 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) approaches. The first representative sample system is L1₀-FePd, as a promising candidate for energy-efficient and non-volatile spintronic devices with large areal densities (down to the 10-nm pitch sizes or even lower). To better address the technological viability of L1₀-FePd for spintronic applications, we systematically examine the impacts of buffer layers (Cr/Pt, Cr/Ru, Cr/Rh, Cr/Ir, and Ir) on the PMA and Gilbert damping of L1₀-FePd during the operating temperature range for spintronic devices (from room temperature to 150°C). Secondly, we demonstrate the spin-strain coupling in Co/Pd multilayers with a strong PMA, which holds promise in strain-assisted magnetic switching. Lastly, we study the magnetization dynamics of synthetic antiferromagnets (SAFs), which has been proposed as a building block in magnetic tunnel junctions (MTJs) to achieve fast and energy-efficient switching. Combining modeling analysis and experimental investigation, we successfully extract detailed information about the cone angles, directions, and phases of spin precession in individual ferromagnetic layers for both high-frequency and low-frequency modes with varying magnetic fields. If time permits, I will also briefly highlight our effort in studying the thermal transport properties (e.g., thermal conductivity) of complex structures, including strongly correlated perovskite oxides and layered “wonder material” of black phosphorus. The structure-property relationships of these technologically important materials established by TR-MOKE open up opportunities for tailoring material properties by structural engineering for applications in spintronic devices with low energy consumption, high thermal stability, and fast switching.

王小佳副教授简历：Xiaojia Wang现任美国明尼苏达大学机械工程系副教授(tenured)，同时就任电子工程系以及化工材料系的博士生导师。2014年加入明尼苏达大学之前，在伊利诺伊大学香槟分校材料科学与工程系进修博后（师从David Cahill教授）。2007至2011年，在佐治亚理工大学机械工程系取得工学博士学位（师从张卓敏教授）。西安交大能源与动力工程学院学士，硕士学位（师从陶文铨教授）。目前的研究方向专注于材料的热物性，界面热输运特性，磁性材料的动力和阻尼特性，自旋电子及磁存储材料的研发及优化。在Nature Communications, Science Advances, Advanced Functional Materials, ACS Nano, 及ACS Applied Materials & Interfaces等多个知名期刊发表科研论文。详细信息请见https://mnttl.umn.edu/publications。