Successful PhD defense of Jibo Zhang

Congratulations to Jibo Zhang!

Title: “Investigation of Weyl Semimetal Mn₃Ge"

Abstract

In this thesis, we prepare non-collinear antiferromagnetic Weyl-semimetal Mn₃Ge thin films by MBE method. The crystal structure and chemical composition of the film are characterized by in-situ RHEED, LEED, STM and XPS, along with the ex-situ AFM, XRD and RBS measurement. Measurements using PPMS, MPMS and ST-FMR reveal the unique magnetic and transport properties of the hexagonal Mn₃Ge film, which are due to the Kagome spin structure of the Mn atoms.
To investigate the possibility of the Mn₃Ge-based AF application, we fabricate the Hall bar devices based on the Mn₃Ge/Pt bilayer structure via ultraviolet lithography and measure the electrical switching of the bilayer’s Hall voltage in the absence of the external magnetic field. The observation can be explained by the seed SOT mechanism in the Mn₃Ge layer. This research provides another method of the electrical manipulation of the magnetic material and shows promise for AF spintronics.