应材料科学与工程学院裴文利副教授邀请，台湾彰化师范大学洪連輝教授、吳仲卿教授来我院进行学术交流，欢迎各位老师和同学参加。
报告时间：4月2日（周一）10:00-12:00
报告地点：EPM四楼报告厅
报告题目：
1、Investigation of Domain-Wall Pinning in A Permalloy Wire
2、Fabrication and Characterization of Nano-scaled Magnetic Tunnel Junctions
报告简介：
1、Pinning behavior of the vortex domain walls investigated by different geometry notches in a permalloy wire. The pattern on samples is made by an injection pad for form a vortex and a Py wire for propagate a domain wall. The injection pad was set as a circular plate of 20 mm diameter and connected to a permalloy wire with width is 2 mm and length is 54 mm. We focused on asymmetric notches to investigate the depinning behavior of vortex domain walls in micron-size magnetic wires. The samples were fabricated by e-beam lithography through lift-off process. The asymmetric notches with difference angles and depth ratios (notch depth divided by wire width) are designed for inspecting depinning field. We measured the domain-wall structures of the magnetic wires using MOKE microscope to obtain the magnetic images. The depinning field is dependent of the vortex domain-wall chirality at depth ratio The difference between the depinning fields of counterclockwise and clockwise vortices is weak at larger depth ratio.
2、Magnetic tunnel junctions have been of an interesting and important subject in the last two decades or so. The driving forces are mainly due to the emerging of the fundamental understanding of the underlying physics of spin dependent transport and the fabrication techniques developed for facilitating many more nowadays application. Most of all, the potential application for the industries of memory, data storage and magnetic field sensing are indeed drawing intensive attention in the science and engineering communities. In this presentation the nanofabrication processes using electron beam lithography in conjunction with ion beam etching for making sub-100 nm scaled magnetic tunnel junctions and the electrical transport properties using the external magnetic field switching and current-driven switching will be illustrated. In addition, many other nanostructures being fabricated for the studies in low dimensional regions will be shown as examples of using a modified electron beam lithography system.
报告人简介：
洪連輝，台湾彰化师范大学教授，物理学院院长。1993年台湾交通大学获得博士学位，先后在台湾彰化师范大学大学担任副教授、教授。洪連輝教授主要从事磁性材料、超导材料的研究。
吳仲卿，台湾彰化师范大学教授，台湾电子自旋研究中心主任。1992年美国University of Oregon获得博士学位，先后在美国University of Oregon和台湾彰化师范大学任研究助理，教授。吳仲卿教授是IEEE Trans.Magn.亚洲区的编委，主要从事电子自旋、磁性纳米材料的研究。
