Date of Award

2022-05-01

Degree Name

Master of Science

Department

Physics

Advisor(s)

Srinivasa R. Singamaneni

Abstract

Probing the magnetism in quasi two-dimensional materials has the potential in driving their properties towards future use in spin electronic based devices. Studying such layered magnets will enable the scientific community to uncover tunable exotic phases such as superconductivity, quantum paramagnetism, etc. This work examines the influence of two types of external perturbations, namely, the pressure and proton irradiation, on the magnetic properties of several compounds in the van der Waals crystal family.

Pressure has been found to induce structural and magnetic phase transitions in many of these materials. Using hydrostatic pressure as a disorderless approach to manipulate the interlayer coupling, we apply pressure to CrBr3, Fe2.7GeTe2, Mn3Si2Te6, and CrSiTe3 with a high-pressure piston cell up to ~1.3 GPa. Materials with weakly held layers allow relatively easy manipulation of the superexchange mechanism. Magnetic property measurements revealed that each material studied has shown the ability to have their corresponding Curie temperature (TC) and the saturation magnetization tuned by pressure. The overall pressure effect on layer separation, bond angle, and exchange coupling are found to strongly influence the change in subsequent magnetic characteristics.

Proton irradiation was employed to manipulate the spin fluctuations on Mn3Si2Te6 (MST) and being irradiated at 1 × 1015, 5 × 1015,1 × 1016, and 1 × 1018 H+/cm2. A critical behavior analysis was performed to examine the physical system at the critical point for each fluence rate. The analytical study of the critical phenomena has been used to discern the magnetic behavior of proton irradiated MST. In this work, we report the critical parameters related to magnetization, magnetic susceptibility, exchange distance, space and spin dimensionality to sort the universality class as a function of proton irradiance.

Language

en

Provenance

Received from ProQuest

File Size

56 p.

File Format

application/pdf

Rights Holder

Rubyann Olmos

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