林昭吟
台湾大学
时间：6月13日上午10：00
地点：唐仲英楼A213
Abstract
In electron strong correlated systems, the competing interactions on the microscopic scale lead to various significant macroscopic effects. Therefore, the related studies are not only scientifically important but also practically valuable. Accordingly, many applications are proposed, including memory devices, ultra fast (THz) optical switch, photovoltaic device, sensor and etc. Among many materials, La0.7Sr0.3MnO3 has advantages of high Curie temperature and high polarization. In addition, its nature of p-type semiconductor makes it a strong candidate for integrating with existing Si technology. In this study, the transport properties of La0.7Sr0.3MnO3/Si-Nanotips heterojunction are studied with varying temperature, electric field and magnetic field. The new findings from our studies including (1) electric-field-assisted magnetoresistance at room temperature is observed; (2) giant positive magnetoresistance occurs at temperature below 50 K, which is ascribed to the field-enhanced spin-flip and electron-electron interaction, and (3) The magnitude of switching resistance is found to be dependent on morphologies, which maybe related to the segregation of Sr on the surface.