Development of Instrumentation for Research on Magnetic Thin Films and Microstructures

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9704222 Erskine This award partially supports the development of unique instrumentation for synthesizing laterally constrained thin film and multilayer magnetic materials and microstructures and for studying novel magnetic phenomena in the structures The new instrument incorporates state-of-the-art thin film growth and characterization capabilities, contact mask and focused ion beam technology capable of creating submicron structures in the films, and complementary high spatial resolution magnetic sensitive spectroscopy/microscopy probes The new instrumentation adds important capabilities to existing research programs of several faculty at The University of Texas which explore thin film magnetism, mesoscopic physics, micromagnetics and magneto-transport phenomena. Scientific issues to be explored based on new capabilities of the instrument include 1) micromagnetic phenomena including properties of magnetic domains in ultrathin films and patterned micron-scale ultrathin film structures; 2) the effects of deliberately induced substrate roughness (atomic steps) and film thickness variations on magnetic domains and related properties including coercive forces and anisotropy of thin films and thin film based microstructures; 3) finite size scaling effects, critical behavior, exchange coupling and dynamical properties of well characterized multilayer and microstructured magnetic systems, and 4) magneto-transport and related magnetic phenomena associated with multilayer films and multilayer- based microstructures. An important feature of the instrument design is the unique combination of materials growth and microstructure fabrication capabilities, materials characterization tools and magnetic sensitive probes which can be used separately or as an integrated system. The instrument consists of three coupled subsystems 1) a thin film growth and characterization chamber incorporating multicell molecular beam epitaxy (MBE) with real-time growth monitoring tools inclu ding Reflection High Energy Electron Diffraction (RHEED) and Auger Electron Spectroscopy (AES); Low Energy Electron Diffraction (LEED) including high resolution spot profile analysis capability; 2) a Magneto-Optic Kerr Effect (MOKE) polarimeter set up for high spatial resolution scanning measurements as well as analysis of hysteresis dynamics; and 3) a high resolution Scanning Electron Microscope with Spin Polarization Analysis (SEMPA) instrument. The SEM/SEMPA instrument is configured to accept a Focused Ion Beam (FIB) column to mill microstructures while viewing the process using SEM. The system is integrated with gate valves and air lock chambers permitting the SEMPA/MOKE subsystem or the MOKE/film growth subsystem to be used independently. %%% This instrumentation has the potential to advance the fundamental knowledge and understanding of thin-film magnetic structure. Such structures have great potential for device applications, which can produce breakthroughs in magnetic device technology.