Date of Award

2024-05-01

Degree Name

Doctor of Philosophy

Department

Materials Science And Engineering

Advisor(s)

Srinivasa R. Singamaneni

Abstract

A new revolutionary application dependent on the electron spin to carry information with greater efficiency in data storage, transfer, and processing, will rely heavily on 2D magnets and the ability to effectively control their electron spins and engineer their properties. Previously, magnetic thin films were heavily studied to achieve this goal, however, these materials came with pitfalls and lacked naturally occurring 2D magnetism. The recent discovery of intrinsic magnetism in few-layered van der Waals (vdW) magnets has inspired researchers to extensively study them because of the feasibility to exfoliate them down to a monolayer. Due to this dimensionality factor, vdW magnets are susceptible to external stimuli opening a new avenue of exploration in the field of 2D magnets. However, the magnetic ordering temperature of these 2D vdW magnets remain quite low (<80 K) for real-world applications. Many research groups began engineering the magnetic properties of these 2D vdW magnets in their few-layered forms to enhance their ordering temperature without understanding how external stimuli affects a many-layered structure first. In this dissertation, two forms of external stimuli are implemented on various bulk vdW magnets. Optical excitation is shown to enhance the magnetization of a quasi-2D vdW magnet CrX3 (X = Cl, I) by targeting its exchange interactions and is corroborated through Electron Spin Resonance spectroscopy. A sub-picosecond optical excitation of another quasi-2D vdW magnet Mn3Si2Te6 (MST) reveals a coherent oscillatory mode that couples directly to the magnetic ordering. Lastly, proton irradiation takes advantage of the spin-lattice coupling in MST and reveals an enhancement in the magnetization at a particular proton fluence through the modification of the exchange interaction. The results presented in this dissertation demonstrate the feasibility to use external stimuli upon quasi-2D vdW magnets and use their exchange interactions as a tunable knob to control their magnetic properties.

Language

en

Provenance

Received from ProQuest

File Size

95 p.

File Format

application/pdf

Rights Holder

Luis Martinez

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