Project 106: Ultrafast Dynamics of Magnons
Contact Information
Asso. Prof. Hao Chu
Email: haochusjtu@sjtu.edu.cn
Project Description and Objectives
When the electron spins align parallel or anti-parallel to each other in a periodic fashion in a solid, they form macroscopically the so-called ferromagnet or antiferromagnet. However, this doesn’t mean the orientation of the individual spins will remain fixed under thermal environment or under optical excitation. In reality, the spins will collectively manifest a spatially varying and periodic precession, known as magnons or spin waves. Experimentally, the characterization of magnon dynamics usually requires large and sophisticated facilities like neutron diffraction station, x-ray diffraction station. It turns out that optics can also be sensitive to the magnetic order inside a solid via the optical Kerr effect. If one employs a femtosecond laser pulse first to excite the individual spins out of their equilibrium alignment and then measures their subsequent re-equilibration using another time-delayed pulse via the optical Kerr effect, one can similarly obtain information about the magnons dynamics.
Eligibility Requirements
Expected candidates are in their 3rd year or 4th year of undergraduate studies, and should have some knowledge about solid state physics as well as equipped with good hands-on skills in the laboratory. Daily communication will be conducted in English.
Main Task
Build a femtosecond ultrafast Kerr-rotation set-up and use it to investigate the magnon dynamics of magnetic materials.
Website
Lab: https://ultrafastandnonlinearopticslab.wordpress.com/
School: http://www.physics.sjtu.edu.cn/