AVS 60th International Symposium and Exhibition
    Electronic Materials and Processing Friday Sessions
       Session EM+NS+TF-FrM

Invited Paper EM+NS+TF-FrM7
Epitaxial Integration of Magnetic Insulators on Silicon

Friday, November 1, 2013, 10:20 am, Room 102 A

Session: Nanoelectronic Interfaces, Materials, and Devices/Crystalline Oxides on Semiconductors
Presenter: A. Posadas, University of Texas at Austin
Correspondent: Click to Email
In recent years, there has been remarkable progress in the growth of complex magnetic oxides in thin film form. Many novel physical properties such as colossal magnetoresistance, multiferroicity, tunneling magnetoresistance effects, and room-temperature ferromagnetism in dilute magnetic oxides have emerged and are ongoing sources of new ideas and systems for applications in the manipulation of the spin of the electron. Part of this field of complex magnetic oxides are materials that are both ferromagnetic and electrically insulating, a relatively rare combination compared to conducting magnetic materials. Such materials are envisioned to serve as spin filtering tunnel barriers, selectively allowing one particular spin to pass through over the other. In this talk, we will focus on insulating ferromagnets with particular emphasis on their growth on silicon substrates. Three insulating ferromagnetic materials systems will be described including the challenges of growing them in epitaxial form on silicon: EuO, strained LaCoO3, and Co-substituted SrTiO3. First we describe the use of Eu metal to form a chemical template on Si, similar to the use of 1/2 monolayer of Sr for the growth of SrTiO3 on Si. We then describe various paths for the growth of EuO on this Eu template. We then describe the use of SrTiO3 on Si as a pseudo-substrate for growing LaCoO3, normally non-magnetic but which becomes ferromagnetic as a result of epitaxial strain, onto silicon. Strain-coupled magnetoresistivity modulation of such LaCoO3/SrTiO3/Si heterostructures will be described. Finally, we describe the growth on Si and properties of Co-substituted SrTiO3, a ferromagnetic insulator at room temperature that may find potential application in spintronics devices. We discuss the effect of Co concentration on the structural and magnetic properties and also describe theoretical calculations indicating magnetism resulting from cobalt-oxygen vacancy centers.