The Interplay of Spin, Charge, and Heat: From Metal/Insulator Heterostructures to Perovskite Bilayers

<p>In this dissertation begin with an investigation of non-local spin transport in an amorphous germanium (a-Ge) sample via the inverse spin Hall effect (ISHE). In that study we show that commonly used techniques such as differential conductance and delta mode of a paired Keithley 6221/2182a for non-local resistance measurements can lead to false indicators of spin transport. Next, we turn out attention to a thickness dependent study in thermally-evaporated chromium (Cr) thin films on a bulk polycrystalline yttrium-iron-garnet (YIG) substrate. This project analyzed the spin transport in the Cr films versus thickness via the longitudinal spin Seebeck effect (LSSE). This research revealed a complex thickness dependence of the spin-to-charge conversion and LSSE voltages for the evaporated Cr that may be a consequence of strain in Cr and finite size effects. We continue to examine LSSE in thermallyevaporated Cr, but now under a temperature dependent study. The results reveal an enhancement in the evaporated Cr below 200 K, where the Cr thin film transitions from a mixed SDW antiferromagnetic state described by the combination of a antiferromagnetic commensurate SDW (CSDW) and paramagnetic incommensurate SDW (ISDW) to a full antiferromagnetic state where both CSDW and ISDW are antiferromagnetic. This is absent in sputtered Cr thin films deposited on similar YIG substrates. Finally, we explore the spin-flopped coupled lanthanum strontium ferrite (LSFO) lanthanum strontium manganite (LSMO) bilayer grown on a lanthanum strontium aluminate (LSAT) substrate. This research focuses on the possible control of magnetic moments using current pulses.</p>

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Year

2024

Author dc:creator

• Bleser, Sam M.

Contributors dc:contributor

• Barry L. Zink
• Xin Fan
• Pavel Salev
• Michelle K. Knowles

• Spin hall effect
• Spincaloritronics
• Spintronics
• Condensed Matter Physics
• Materials Science and Engineering
• Other Materials Science and Engineering
• Physical Sciences and Mathematics
• Physics

Statement dc:rights

• <p>Copyright is held by the author. User is responsible for all copyright compliance.</p>

Language dc:language

English (eng)

Repository record dc:identifier

https://digitalcommons.du.edu/etd/2371

OAI identifier oai:identifier

oai:digitalcommons.du.edu:etd-3356