MBE growth and physical properties of Cr₂Te₃ thin films

Abstract

In this thesis work, single crystal Cr₂Te₃ thin films were successfully grown by the Molecular Beam Epitaxy technique. Crystal structure characterizations and chemical composition analyses were done on these materials. Corresponding analyses were conducted to uncover their novel physical properties. Ferromagnetic ordering and Anti-ferromagnetic ordering was confirmed to co-exist in the as–grown Cr₂Te₃ thin film samples. Perpendicular magnetic anisotropy effect was found on them. The Curie temperature of Cr₂Te₃ was enhanced by increasing the electron concentration and a relationship between the Curie temperature and the c-lattice parameter of Cr₂Te₃ was found. Curie temperature of Cr₂Te₃ grown on sapphire can be improved up to room temperature. The substrate plays a key role in changing the carrier type in the thin film samples from holes to electrons. This work lays the material foundation for applications of Cr₂Te₃ based–magnetic devices. Anomalous Hall effect (AHE) was observed in these thin film samples as well. The sign changing in the AHE loop at different temperatures was discussed in detail.

Date of Award	2018
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology