Magnetic effects at complex oxide interfaces
Abstract/Contents
- Abstract
- Control, manipulation, and measurement of the spin state of electrons, termed spintronics, has been critical to the development of magnetic memory devices which have dominated non-volatile data storage in computers, servers, and often even media formats. Likewise, performing computational operations using electron spins is under active development to supplement, or in some cases replace, traditional charge based logic. Complex oxides are a powerful tool for spintronics as their strong electron interactions and correlations lead to unique and powerful spin functionality. The myriad interesting phenomena observed in complex oxides, from multiferroics to high Tc superconductors, suggests not only their viability as spintronic materials but also the ability to couple the relevant spin operations to a wide variety of novel functionalities. In this work, complex oxide materials are investigated to explore two spintronics opportunities. The first half of this research attempts to introduce a spin-polarized conducting interface between two diamagnetic, insulating materials. The second half explores spin-pumping behavior in the previously unutilized spinel ferrites. One avenue for the development of spintroincs is the concept of "materials by design" where material properties and functionality are tuned or introduced through their nanostructure or interfaces. A leading example of this paradigm is the LaAlO3/SrTiO3 interface where conductivity is observed between two insulating materials. Magnetic ordering at the interface has been inconsistently observed in previous studies, however generation of a spin-polarized conduction layer on-demand would be extremely useful for spintronic devices. Therefore, this work pursues this emergent spin phenomenon by introducing magnetic dopants at the interface. The system is observed to be electrically and magnetically unaffected by the presence of the dopants however. Furthermore, no evidence for magnetic ordering is observed in undoped LaAlO3/SrTiO3 systems, drawing into question the intrinsic origin of the previously observed magnetic moments. The remainder of this work is devoted to characterizing spin pumping in a previously unexplored class of materials, the spinel ferrites. Here "pure" spin currents, where spin moments are transported without net charge flow, are generated in adjacent metals, and the efficiency is characterized through the spin-mixing conductance at the spinel-ferrite/metal interface. The order-of-magnitude improvement in intrinsic damping and a spin-mixing conductance competitive with literature-leading systems indicate Ni0.65Zn0.35Al0.8Fe1.2O4 to be a viable spin-pumping material. The design parameters of this model system can be extracted to myriad other spinel materials and paves the way for future all-oxide spin-pumping systems.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2017 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Gray, Matthew Thomas |
|---|---|
| Associated with | Stanford University, Department of Materials Science and Engineering. |
| Primary advisor | Suzuki, Yuri, (Applied physicist) |
| Primary advisor | Wang, Shan |
| Thesis advisor | Suzuki, Yuri, (Applied physicist) |
| Thesis advisor | Wang, Shan |
| Thesis advisor | Hwang, Harold Yoonsung, 1970- |
| Thesis advisor | White, Robert |
| Advisor | Hwang, Harold Yoonsung, 1970- |
| Advisor | White, Robert |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Matthew Thomas Gray. |
|---|---|
| Note | Submitted to the Department of Materials Science and Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2017. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2017 by Matthew Thomas Gray
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
Also listed in
Loading usage metrics...