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  • Cooling-field dependence of exchange bias effect in La 0.45Sr0.55MnO3 nanoparticles 

    VENKATESAN, MUNUSWAMY; COEY, JOHN MICHAEL DAVID (2014)
    Magnetic properties of 16 nm La0.45Sr0.55MnO3 nanoparticles exhibit superparamagnetic blocking at 160 K with a ferromagnetic moment appearing in the antiferromagnetic state. The exchange interaction at the interface between ...
  • Correlation between perpendicular exchange bias and magnetic anisotropy in IrMn/[Co/Pt](n) and [Pt/Co](n)/IrMn multilayers 

    VAN DIJKEN, SEBASTIAN; COEY, JOHN MICHAEL DAVID (American Institute of Physics, 2005)
    Perpendicular exchange bias has been observed for IrMn/[Co/Pt]n and [Pt/Co]n/IrMn multilayers in the as-deposited state. The exchange bias field is largest when the IrMn film is grown on magnetically saturated Co/Pt ...
  • CoTaZr/Pd multilayer with perpendicular magnetic anisotropy 

    COEY, JOHN MICHAEL DAVID (AIP Publishing, 2013)
    We report a novel perpendicularly magnetized thin film [Co91.5 Ta 4.5Zr4/Pd]5 multilayer, which exhibits strong perpendicular magnetic anisotropy when grown on 5 nm of Pd and Ru seed layers. The Pd-seeded multilayer annealed ...
  • Critical behavior of La0.75Sr0.25MnO3 

    COEY, JOHN MICHAEL DAVID (American Physical Society, 2002)
    Magnetization, susceptibility, and specific heat measurements were made on a single crystal of La0.75Sr0.25MnO3. The ferromagnetic-to-paramagnetic phase transition was found at 346 K and four critical exponents were measured ...
  • Crystal Fields in Nd2Fe14B 

    COEY, JOHN MICHAEL DAVID (American Physical Society, 1984)
    The leading terms in the crystal field at both rare-earth sites in the new permanent magnet alloy Nd2Fe14B are B20 and B22s. The sign of B20 explains the variation of the anisotropy constant K1 reported by Sagawa et al. ...
  • Cubic Mn 2 Ga Thin films: Crossing the spin gap with ruthenium 

    STAMENOV, PLAMEN; VENKATESAN, MUNUSWAMY; COEY, JOHN MICHAEL DAVID; RODE, KARSTEN (2014)
    Cubic Mn2Ga films with the half-Heusler C1b structure are grown on V (001) epitaxial films. The phase is a soft ferrimagnet, with Curie temperature TC = 225 K and magnetization Ms=280  kA m−1, equivalent to 1.65μB per ...
  • Current trends in amorphous magnetism 

    COEY, JOHN MICHAEL DAVID (IEEE, 1984)
    Recent research on some topics in amorphous magnetism is reviewed and questions are posed which should be answered by future work. The topics are i) appearance of magnetism in binary alloys of the 3d transition elements ...
  • Cylindrical permanent-magnet structures using images in an iron shield 

    COEY, JOHN MICHAEL DAVID (IEEE, 2003)
    We report on cylindrical permanent-magnet structures that exploit the image effect in a surrounding circular soft-iron sheath. We present the theory for a general multipole ring, where the polarization direction ? = (n + ...
  • Cylindrical permanent-magnet structures using images in an iron shield 

    Peng, Quanling; MCMURRY, SARA; COEY, JOHN MICHAEL DAVID (IEEE, 2003)
  • Dependence of charge carrier injection on the interface energy barrier in short-channel polymeric field effect transistors 

    COEY, JOHN MICHAEL DAVID; STAMENOV, PLAMEN (2012)
    The influence of contact materials on the electrical characteristics of field-effect transistors made from poly(3-hexylthiophene) with short-channel lengths of 80nm is investigated. The thermally activated output current ...
  • Diameter-modulated ferromagnetic CoFe nanowires 

    VENKATESAN, MUNUSWAMY; COEY, JOHN MICHAEL DAVID (2013)
    Highly ordered nanoporous anodic aluminium oxide templates with uniform or periodically modulated pore diameters have been fabricated by the hard-pulse anodization technique. Straight and diameter-modulated CoFe nanowires ...
  • Domain-wall dynamics in aligned bound Sm2Fe17 

    COEY, JOHN MICHAEL DAVID (American Physical Society, 1996)
    ac susceptibility (?ac=??-j??) of an aligned bound Sm2Fe17 powder sample has been measured along the easy direction as a function of temperature, frequency, warming rate, and time. Anomalous behavior has been found in that ...
  • Dynamic response of ammonia sensors constructed from polyaniline nano?bre ?lms with varying morphology 

    COEY, JOHN MICHAEL DAVID; STAMENOV, PLAMEN (Elsevier, 2012)
    Polyaniline is acid-doped with HCl, HNO3, HClO4, HBr or H2SO4 to yield thin films that are nanofibrous or dense. The nanofibrous films show a faster response to ammonia gas, and the response is greater when the films are ...
  • The effect of magnetic annealing on barrier asymmetry in Co40Fe40B20/MgO magnetic tunnel junctions 

    COEY, JOHN MICHAEL DAVID; FENG, JIA-FENG (2010)
    We demonstrate that high-quality magnetic tunnel junctions with Co40Fe40B20 electrodes and crystalline MgO barriers, which show a 230% tunneling magnetoresistance ratio at room temperature, can be successfully fabricated ...
  • Effects of Fe, Cu, Zr, and Ti on the magnetic properties of SmCo-1:7 magnets 

    VENKATESAN, MUNUSWAMY; COEY, JOHN MICHAEL DAVID (IEEE, 2002)
    The effect of Fe, Cu, Zr, and Ti substitution on magnetic properties of SmCo 1 : 7 magnets at temperatures up to 500 C were studied. As-milled amorphous Sm(Co,Fe,Cu,Ti???Zr)7 magnets crystallized in the TbCu7-type ...
  • Electrodeposited FePt films 

    COEY, JOHN MICHAEL DAVID (IEEE, 2003)
    A novel bath for electrodepositing FePt films was developed and films were electrodeposited on copper substrates with thickness up to 0.45 m. The magnetic and structural properties of the films were measured. The films ...
  • Electrodeposition of coercive L10 FePd and FePt magnets 

    COEY, JOHN MICHAEL DAVID (Elsevier, 2010)
    We report the preparation, characterization of structure and magnetic properties of electrodeposited L10 FePt films with high coercivity. Equiatomic as-deposited films are nanocrystalline, soft and magnetically isotropic. ...
  • Electron and spin transport studies of gated lateral organic devices 

    COEY, JOHN MICHAEL DAVID; STAMENOV, PLAMEN (2012)
    In view of the many, often contradictory, reports of magneto-resistance (M R) in spin valve stacks containing a layer of organic semiconductor, mostly of the small molecule variety, we have investigated interdigitated ...
  • Electron localization in mixed-valence manganites 

    COEY, JOHN MICHAEL DAVID (American Physical Society, 1995)
    Mixed-valence manganites (A3+0.7B2+0.3)MnO3 exhibit a resistivity peak with giant negative magnetoresistance below the Curie point. Residual resistivity ranges from 5?10-8 to 8?103 m, but the electronic heat capacity when ...
  • Electronic properties of Sr14Cu24O41 

    COEY, JOHN MICHAEL DAVID (American Physical Society, 1989)
    Crystals of orthorhombic Sr14Cu24O41 are semiconducting, with an activation energy of 0.18(2) eV for conduction along c, the direction lying parallel to both the (Cu2O3) planes and the (CuO2) chains. The magnetic susceptibility ...