飞秒脉冲激光激励下亚铁磁合金薄膜的超快磁动力学研究

项目名称： 飞秒脉冲激光激励下亚铁磁合金薄膜的超快磁动力学研究

项目编号： No.51471118

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 一般工业技术

项目作者： 刘要稳

作者单位： 同济大学

项目金额： 85万元

中文摘要： 脉冲激光激励下稀土-过渡金属亚铁磁薄膜的超快磁动力学研究近些年引起广泛关注。特别是近期报道的由飞秒激光在几十飞秒甚至更短的时间内可以驱动磁化翻转的实验成果，有望在未来超快磁存储技术中得到重要应用；其中磁化强度的翻转可以通过飞秒激光提供的热效应，或是圆偏振光通过逆法拉第效应产生翻转磁场来实现。但有关上述两种磁翻转的微观物理机制目前尚处于起步研究阶段，有待深入探讨。本项目我们将针对这一前沿科学问题开展研究，借助我们自行开发的微磁学模拟程序，研究激光驱动的稀土原子和过渡金属原子之间的磁动力学差异；揭示脉冲激光诱导的热效应和逆法拉第效应的行为特性和微观机理，进而区分两效应在激光驱动磁化翻转过程中的贡献；研究亚铁磁材料的内稟阻尼特性。我们期望这一研究将有助于加深对激光驱动超快磁动力学的理解，推动自旋电子学的发展。

中文关键词： 磁性薄膜；微磁学；亚铁磁材料；超快磁动力学

英文摘要： Laser-induced magnetization dynamics in rear-earth (RE)-transient-metal (TM) alloys has attracted great attention in the past several years. What has particular interesting is that the ultrafast magnetization switching within several tens of femtoseconds and even faster has been reported recently by means of femtosecond laser pulses, which has high potential for future ultrafast data-storage applications. The laser provides either the heating effect via energy transfer or the switching field via the inverse Faraday effect. However,the microscopic understanding of the underlying processes of such an optically induced magnetization reversal are just getting started, and some deep insights of the mechanism are still unclear. In this project, such a frontier scientific issue will be studied by using an in-house developed micromagnetic simulation technique. The difference of magnetic dynamics between the TM atoms and RE atoms will be firstly clarified. Then, we will focus on the characteristics and the mechanism of the heating effect and inverse Faraday effect, which shall identify the different contributions of the two effects for the laser-induced switching. Finally, we will study the intrinsic damping of the RE-TM amorphous films. We expect the proposed study shall open new insights into the understanding of laser-induced ultrafast magnetization dynamics and provide significant development in spintronics.

英文关键词： Magnetic thin film;Micromagnetic simulation;Ferrimagnetic materials;Ultrafast magnetization dynamics