Cylindrical Nanowires for Water Splitting and Spintronic Devices

  • Julian Moreno Garcia

Student thesis: Doctoral Thesis

Abstract

Energy enables basic and innovative services to reach a seemingly ever-growing population and when its generation costs are reduced or when its usage is optimized it has the greatest impact on the reduction of poverty. Furthermore, there is a pressing need to decouple energy generation from non-renewable and carbon-heavy sources which has led mayor economies to increase research efforts in these areas. This thesis discusses research on water oxidation using nanostructured iron oxide electrodes and current-induced magnetic domain wall motion in nickel/cobalt bi-segmented nanowires. These two fields may seem disparate at first glance, but are linked by such common theme: materials for energy, and more precisely, materials for energy conversion and economy. The work presented in this document aims also to reflect this theme by using widely available materials like iron and aluminum, and optimizing the methods to produce the final samples using the least resources possible. All samples were prepared by electroplating metals (iron, cobalt and nickel) into anodized alumina templates fabricated inhouse. For water oxidation, iron nanorods were integrated into an electrode and annealed in air, while nickel/cobalt nanowires were isolated and contacted individually to test for spintronics-related effects. Spintronic-based devices aim to reduce energy usage in nowadays microelectronic devices. The nanostructured iron oxide electrode showed its usefulness for water oxidation in a laboratory environment, making it an appropriate complement to other electrodes specially designed for water reduction in a photoelectrochemical cell. This two-electrode design, allows for hydrogen and oxygen to be produced at each electrode and therefore eases their separate collection for, e.g., fuel or fertilizers. On the other hand, this work presents one of the first experimental demonstration of current-induced domain wall motion in soft/hard cylindrical magnetic nanowires at zero applied external magnetic field. These kinds of experiments are expected to be the first of many which will allow researchers in the field to test for spintronic-relevant properties and interactions in cylindrical magnetic nanowires.
Date of AwardJun 10 2021
Original languageEnglish (US)
Awarding Institution
  • Physical Science and Engineering
SupervisorJurgen Kosel (Supervisor)

Keywords

  • Cylindrical Nanowires
  • Spintronics
  • Water oxidation
  • Domain wall motion
  • Micromagnetics

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