Abstract
In a world of fast development where microelectronics has been a large and inevitable part of society, there has never been higher demand for new materials allowing new functionalities in electronic devices as there is today. Here, the metallic interface between the two insulators LaAlO3 and SrTiO3 opens up the field of oxide electronics due to the vast range of properties this heterostructure exhibits, as well as the ability to tune these properties. However, it remains an open question as to why the LaAlO3/SrTiO3 system can display such a versatile palette of physical properties, where, e.g., magnetism forms in the heterostructure despite the parent materials being nominally non-magnetic.
In this thesis, the focus is aimed at understanding how the interfacial magnetism and conductivity in SrTiO3-based heterostructures are influenced by fabrication methods, strain, and oxygen vacancy doping. The findings of this thesis improve our basic understanding of these heterostructures and stimulate exploration of new devices being utilized in integrated circuits used in new electronics.
In each chapter of the thesis, I highlight an important aspect for understanding the heterostructures. The thesis is constructed as follows.
Chapter 1 starts with a brief introduction to the SrTiO3-based system, which is the building block of the studied heterostructures.
Chapter 2 presents the applied experimental methods for fabricating the samples, which includes the termination procedures for substrate surfaces, film growth by pulsed laser deposition, and deposition monitoring by reflecting high energy electron diffraction, as well as characterization techniques such as magnetotransport used to investigate the materials in this study.
Chapter 3 describes the fabrication of freestanding oxide membranes. The methods used in this thesis typically rely on releasing thin oxide films using sacrificial interlayers and selective etching in addition to freestanding oxide membranes formed spontaneously during growth.
Chapter 4 describes the properties of the freestanding membranes that show the possibility of tweaking oxygen diffusion, but still preserve properties such as superconductivity in the freestanding form.
Chapter 5 deals with the magnetic properties of the SrTiO3-based system and the dependence on the deposition process and post-processing using annealing.
Chapter 6 describes the relationship between band structure and process parameters SrTiO3-based systems by surface treatment, annealing, Sr diffusion in anatase-TiO2/SrTiO3 and introduction of an additional buffer layer.
Chapter 7 concludes the thesis and provides an outlook.
In this thesis, the focus is aimed at understanding how the interfacial magnetism and conductivity in SrTiO3-based heterostructures are influenced by fabrication methods, strain, and oxygen vacancy doping. The findings of this thesis improve our basic understanding of these heterostructures and stimulate exploration of new devices being utilized in integrated circuits used in new electronics.
In each chapter of the thesis, I highlight an important aspect for understanding the heterostructures. The thesis is constructed as follows.
Chapter 1 starts with a brief introduction to the SrTiO3-based system, which is the building block of the studied heterostructures.
Chapter 2 presents the applied experimental methods for fabricating the samples, which includes the termination procedures for substrate surfaces, film growth by pulsed laser deposition, and deposition monitoring by reflecting high energy electron diffraction, as well as characterization techniques such as magnetotransport used to investigate the materials in this study.
Chapter 3 describes the fabrication of freestanding oxide membranes. The methods used in this thesis typically rely on releasing thin oxide films using sacrificial interlayers and selective etching in addition to freestanding oxide membranes formed spontaneously during growth.
Chapter 4 describes the properties of the freestanding membranes that show the possibility of tweaking oxygen diffusion, but still preserve properties such as superconductivity in the freestanding form.
Chapter 5 deals with the magnetic properties of the SrTiO3-based system and the dependence on the deposition process and post-processing using annealing.
Chapter 6 describes the relationship between band structure and process parameters SrTiO3-based systems by surface treatment, annealing, Sr diffusion in anatase-TiO2/SrTiO3 and introduction of an additional buffer layer.
Chapter 7 concludes the thesis and provides an outlook.
| Original language | English |
|---|
| Place of Publication | Kgs. Lyngby |
|---|---|
| Publisher | Technical University of Denmark |
| Number of pages | 233 |
| Publication status | Published - 2023 |
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Dive into the research topics of 'SrTiO3-based oxides: A versatile platform for emerging magnetic and electronic properties'. Together they form a unique fingerprint.Projects
- 1 Finished
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Strain controlled electronics properties of complex oxide heterostructures
Dahm, R. T. (PhD Student), Eom, C.-B. 0. (Examiner), Gunkel, F. (Examiner), Pryds, N. (Main Supervisor), Christensen, D. V. (Supervisor) & Esposito, V. (Supervisor)
01/11/2019 → 14/06/2023
Project: PhD
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