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Now showing items 21-36 of 36

  • Magnetic, magnetotransport, and optical properties of Al-doped Zn0.95Co0.05O thin films 

    VENKATESAN, MUNUSWAMY; COEY, JOHN MICHAEL DAVID (American Institute of Physics, 2007)
    Thin films of 5% Co-doped ZnO with a range of Al codoping exhibit a band-edge shift, which varies with carrier concentration as n2/3. Carrier effective mass is 0.26me and mobility is ~ 10?cm2?V?1?s?1. The doped films, which ...
  • Magnetism in dilute magnetic oxide thin films based on SnO2 

    STAMENOV, PLAMEN; COEY, JOHN; VENKATESAN, MUNUSWAMY (2006)
    Thin films of SnO2 prepared by pulsed-laser deposition on R-cut sapphire substrates exhibit ferromagnetic properties at room temperature when they are doped with Cr, Mn, Fe, Co, or Ni, but not with other 3d cations. ...
  • Magnetism in hafnium dioxide 

    COEY, JOHN MICHAEL DAVID; VENKATESAN, MUNUSWAMY (2005)
    Thin films of HfO2 produced by pulsed-laser deposition on sapphire, yttria-stabilized zirconia, or silicon substrates show ferromagnetic magnetization curves with little hysteresis and extrapolated Curie temperatures far ...
  • Magnetism in thin films of CaB6 and SrB6 

    LUNNEY, JAMES GERARD; COEY, JOHN MICHAEL DAVID; LUNNEY, JAMES GERARD; VENKATESAN, MUNUSWAMY; COEY, JOHN MICHAEL DAVID (American Physical Society, 2004)
    Thin films of disordered hexaborides CaB6 and SrB6 deposited by pulsed-laser deposition on MgO (100) or Al2O3 (001) substrates are ferromagnetic. A typical room-temperature moment per unit area of substrate is 350 mB ...
  • Magnetization Process in Dilute Magnetic Oxides 

    VENKATESAN, MUNUSWAMY; COEY, JOHN MICHAEL DAVID; STAMENOV, PLAMEN (2010)
    Thin films of dilute magnetic oxides often exhibit high-temperature ferromagnetism with magnetization curves of the form M approximate to M-s tanh(H/H-0); the curves are practically anhysteretic and temperature-independent ...
  • Magnetoresistance of Co-doped ZnO thin films 

    STAMENOV, PLAMEN; COEY, JOHN; VENKATESAN, MUNUSWAMY (2006)
    Longitudinal, transverse, and perpendicular magnetoresistances were investigated at temperatures 1.2 T 300 K in fields of up to 20 T for four ZnO films: one undoped, two with 4% Co one paramagnetic, the other exhibiting ...
  • New two in one magnetic fluorescent nanocomposites 

    VENKATESAN, MUNUSWAMY; GOUNKO, IOURI (SPIE, 2005)
    Magnetite nanoparticles have been coated by a porphyrin derivative to produce new magnetic materials with fluorescent properties. The magnetic nanoparticles were prepared using two different methods, one based on sol-gel ...
  • Origin of the Two-Dimensional Electron Gas at LaAlO3=SrTiO3 Interfaces: The Role of Oxygen Vacancies and Electronic Reconstruction 

    COEY, JOHN; VENKATESAN, MUNUSWAMY (2013)
    The relative importance of atomic defects and electron transfer in explaining conductivity at the crystalline LaAlO3=SrTiO3 interface has been a topic of debate. Metallic interfaces with similar electronic properties ...
  • Site-specific order and magnetism in tetragonal Mn3Ga thin films 

    STAMENOV, PLAMEN; SANVITO, STEFANO; VENKATESAN, MUNUSWAMY (2013)
    Mn 3 Ga bulk material and thin films deposited on several different substrates have been investigated using x-ray and neutron diffraction, x-ray absorption spectroscopy, x-ray magnetic circular dichroism, and ...
  • Site-specific order and magnetism in tetragonal Mn3Ga thin films 

    STAMENOV, PLAMEN; COEY, JOHN; RODE, KARSTEN; SANVITO, STEFANO; VENKATESAN, MUNUSWAMY (2013)
    Mn 3 Ga bulk material and thin films deposited on several different substrates have been investigated using x-ray and neutron diffraction, x-ray absorption spectroscopy, x-ray magnetic circular dichroism, and ...
  • SnO2 doped with Mn, Fe or Co: Room temperature dilute magnetic semiconductors 

    VENKATESAN, MUNUSWAMY; COEY, JOHN MICHAEL DAVID (American Institute of Physics, 2004)
    Room temperature ferromagnetism is found in (Sn1?xMx)O2 (M=Mn, Fe, Co, x=0.05) ceramics where x-ray diffraction confirms the formation of a rutile-structure phase. Room temperature saturation magnetization of 0.2 and 1.8 ...
  • Soft x-ray spectroscopic investigation of ferromagnetic Co-doped ZnO 

    LUNNEY, JAMES GERARD; MCGUINNESS, CORMAC; PATTERSON, CHARLES HUBERT; VENKATESAN, MUNUSWAMY; COEY, JOHN MICHAEL DAVID (American Institute of Physics, 2006)
    The electronic properties of cobalt-doped ZnO were investigated through site-selective and element-sensitive x-ray-absorption spectroscopy in the vicinity of the Co L2,3 edge, the oxygen K edge, and at the Zn L3 edge. ...
  • Superparamagnetism in MgO-based magnetic tunnel junctions with a thin pinned ferromagnetic electrode 

    COEY, JOHN MICHAEL DAVID; VENKATESAN, MUNUSWAMY (2010)
    MgO-based magnetic tunnel junctions have been fabricated with a thin Co40Fe40B20 (CoFeB) layer in the pinned synthetic antiferromagnetic CoFe/Ru/CoFeB stack. An inverted tunneling magnetoresistance is observed due to the ...
  • Tunnel magnetoresistance of disordered low-moment Co2MnSi Heusler alloy films 

    VENKATESAN, MUNUSWAMY; COEY, JOHN MICHAEL DAVID (American Institute of Physics, 2005)
    Thin films of Co(1?x?y)MnxSiy (x = 0.18?0.26 and y = 0.23?0.29) were deposited from elemental targets onto thermal-oxidized Si substrates at room temperature using dc magnetron cosputtering. The as-deposited films appear ...
  • Vortex states in soft magnets in two and three dimensions 

    COEY, JOHN MICHAEL DAVID; DIAO, ZHU; VENKATESAN, MUNUSWAMY (2010)
    The magnetization curves of arrays of near-spherical soft ferromagnetic particles are compared with those of quasi-two-dimensional dots with similar radius prepared by a rapid e-beam lithographic technique. Curves for the ...
  • The zero-magnetization Heusler ferrimagnet 

    COEY, JOHN; VENKATESAN, MUNUSWAMY; RODE, KARSTEN; ACKLAND, KARL (2013)
    An unusual zero-moment half-metallic state has been predicted in stoichiometric Heusler compounds with 24 valence electrons, where, unlike an antiferromagnet, the two sublattices are chemically or crystallographically ...