Growth and Development of Meta-Multiferroic Systems using Pulsed Electron Deposition

Meta-multiferroic systems exhibit unique properties and hold the potential for novel device functionality due to the simultaneous showing of ferroelectric and magnetic ordering in these materials. The direct or indirect coupling of these order parameters only adds to their usefulness and scientific intrigue. Recent advances in thin film deposition technology along with collaborative efforts between experimentalists and theoreticians have led to a renewed interest in these materials in the past decade.;In this dissertation, a PED tool equipped with two electron gun sources was used to experimentally explore the capabilities of this tool to grow high quality thin films of oxide materials of significant importance to the study of meta-multiferroic systems. Thin films of the multiferroic oxide Bismuth Ferrite (BiFeO3), the ferrimagnetic oxide Magnetite (Fe3O 4), and the conducting oxide Strontium Ruthenate (SrRuO3) were grown by PED. The influences of deposition parameters on the electrical, magnetic, structural, chemical and morphological properties of the films were characterized. Optimal deposition conditions for each material were identified and subsequent growth of bilayers consisting of BFO/SRO and Fe3O 4/BFO were grown. The ferroelectric domain structure of BFO was mapped using piezo force microscopy and switching of the polarization direction was achieved through application of an electrical bias to the film; demonstrating control of the domain structure within this material. Exchange coupling was developed in the Fe3O4/BFO bilayers through a magnetic field cooling procedure. This is the first demonstration of exchange bias with these two materials and establishes a foundation upon which subsequent studies can build our understanding of magneto-electric coupling and the influence of film properties in composite systems on the development and control of coupled electrical and magnetic ordering.;The results of this work demonstrate the viability of PED as a tool capable of producing high quality thin film oxide materials. The range of material properties observed through variation of growth parameters provides insight into the application of PED to a wide range of systems. In addition, the oxide films grown in this study were found to display properties particularly interesting for the exploration of meta-multiferroic systems and the advancement of research efforts to develop a device capable of providing room temperature electrical control of magnetism.;A novel deposition technique called Pulsed Electron Deposition (PED) has recently been developed which may provide researchers with a new means of producing films of equal or better quality to more conventional methods such as Pulsed Laser Deposition, Sputtering, and MBE currently used to study multiferroic materials. Pulsed electron deposition utilizes a channel spark process to generate short pulses of high energy electrons which are directed into a target, causing rapid heating and ejection of the target material which can then be captured by an appropriately placed growth template to produce thin films. PED has been used to grow a number of materials such as the superconducting oxides like YBCO, glassy materials like borosilicate, polymers (PTFE) and even metals with a low heat conductivity coefficient (Sn, Zn, Fe, Ti, and their alloys), though the technique is still in its infancy.