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  • Magnetization and Temperature Dependence of the Mossbauer Spectrum Shift for an Insulator. 

    COEY, JOHN MICHAEL DAVID (American Physical Society, 1969)
    The results of a Mossbauer-effect study of HoFeO3 in the temperature range 99-875?K are presented. Special attention is paid to the shift of the center of the spectrum and its temperature dependence both above and below ...
  • Noncollinear spin arrangement in ultrafine ferrimagnetic crystallites 

    COEY, JOHN MICHAEL DAVID (American Physical Society, 1971)
    Mossbauer-effect measurements on extremely small (~60 ?) crystallites of ?-Fe2O3 show that the spin configuration differs from the Neel type found in large crystallites. It is proposed that the ions in the surface layer ...
  • Mossbauer spectra of mixed crystals: diamagnetically - substituted yttrium iron garnet in the critical region 

    COEY, JOHN MICHAEL DAVID (American Physical Society, 1972)
    There is a range of temperature where the Mossbauer spectra of 57Fe3+ in diamagnetically substituted magnetically ordered iron oxides show broad lines and may be reproduced by local-molecular-field theory. The lines can ...
  • Nickel sulfide - an itinerant electron antiferromagnet. 

    COEY, JOHN MICHAEL DAVID (American Physical Society, 1974)
    Antiferromagnetic nickel sulphide has a small temperature-independent magnetic susceptibility. The ordered moment per nickel atom, measured with neutrons, decreases from 1.45?B to 1.00?B at 4.2 K with a decrease of 0.6% ...
  • Heat capacity of nichel sulfide and its semimetal-metal transition 

    COEY, JOHN MICHAEL DAVID (American Physical Society, 1974)
    Heat-capacity measurements have been made from 5 to 330 K on NiS which shows a nonmetal-metal transition at 265 K, and on Ni0.95S which is metallic at all temperatures. The low-temperature data yield electronic specific-heat ...
  • Heat capacity and metal-insulator transition in Ti4O7 single crystals' 

    COEY, JOHN MICHAEL DAVID (American Physical Society, 1974)
    Heat-capacity and entropy changes at the metal-insulator transitions have been measured on Ti4O7 single crystals. The 130-K transition is related to a disordering of the Ti3+ and Ti4+ chains at the unit cell level. Ti3+ ...
  • Magnetic structure of an amorphous rare-earth transition-metal alloy 

    COEY, JOHN MICHAEL DAVID (American Physical Society, 1976)
    161Dy Mossbauer spectra show that the dysprosium moments in amorphous DyCo3.4 are strongly coupled to the local crystal field axes. The magnetic structure is one in which the cobalt "sublattice" is strongly ferromagnetic, ...
  • Comparison between the amorphous and crystalline (A15) phases of Nb3Ge 

    COEY, JOHN MICHAEL DAVID (American Physical Society, 1978)
    A comparative study on the superconducting and the normal-state properties of the amorphous, low-Tc (3.9 K) and the crystalline, high-Tc (2.18 K) phases of Nb3Ge suggests that changes in the strength of electron-phonon ...
  • 'Pulsed X-ray shadowgraphy of dense, cool, laser-imploded plasma 

    LUNNEY, JAMES GERARD (American Physical Society, 1978)
    Laser implosion of 87-bar neon-filled glass microballoon targets produces a dense, cool plasma whose development in time and space is recorded by pulsed-x-ray shadowgraphy with soft x rays from a separate laser-produced ...
  • Measurement of fast-electron energy spectra and preheating in laser-irradiated targets 

    LUNNEY, JAMES GERARD (American Physical Society, 1979)
    Fast electrons produced by the irradiation of plane-layered targets with 20-J, 100-ps, 1015-W.cm-2, neodymium-laser pulses have been diagnosed by the K? emission which they cause at various depths in the targets. The ...
  • Time-resolved X-ray spectroscopy of laser produced plasmas 

    LUNNEY, JAMES GERARD (American Physical Society, 1980)
    X-ray emission spectra, produced by irradiation of neon-filled aluminum-coated glass microballoon and plane aluminum targets, with 100-ps Nd-glass laser pulses, have been time resolved with an x-ray streak camera. The time ...
  • The X-ray spectroscopic diagnosis of laser-produced plasmas, with emphasis on line broadening 

    LUNNEY, JAMES GERARD (American Physical Society, 1980)
    A detailed account is given of the x-ray spectroscopic diagnosis of plasmas formed by exploding pusher microballoons. The measurements of the electron temperature from the shell and from the core is described. A method for ...
  • Silicon satellite spectra from laser imploded microballoons 

    LUNNEY, JAMES GERARD (American Physical Society, 1981)
    The dielectronic satellite spectral lines, on the long-wavelength side of the hydrogenic Si XIV Lyman-? line, have been observed in the space-resolved spectra from laser-imploded glass microballoons. In the electron density ...
  • Atomic coordination and the distribution of electric field gradients in amorphous solids 

    COEY, JOHN MICHAEL DAVID (American Physical Society, 1981)
    The observation of nuclear quadrupole interactions in amorphous solids provides a unique possibility of obtaining information about the angular distribution of local ionic coordinations, complementary to the information ...
  • Charge-Transfer and Non-Rigid-Band Effects in the Graphite Compound LiC6 

    MC GOVERN, IGNATIUS (1981)
    A comparison of angle-resolved photoemission energy distributions for pure graphite and the intercalation compound LiC6 show that considerable charge is transferred from Li to C, as expected; but the valence bands do not ...
  • Numerical study of conductivity for the Anderson model in two and three dimensions 

    WEAIRE, DENIS LAWRENCE (1981)
    The equation-of-motion method is applied to the calculation of the conductivity for the Anderson model in two and three dimensions. The Kubo-Greenwood formula is evaluated by averaging suitable combinations of time-dependent ...
  • 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 ...
  • 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. ...
  • Computer generation of structural models of amorphous Si and Ge 

    WEAIRE, DENIS LAWRENCE (1985)
    We have developed and applied a computer algorithm that generates realistic random-network models of a-Si with periodic boundary conditions. These are the first models to have correlation functions that show no serious ...
  • Optical phase conjugation In a soluble polymer 

    BLAU, WERNER (1986)
    Degenerate four-wave mixing of picosecond light pulses in polydiacetylene dissolved in toluene has been observed. Phase conjugate reflectivities of over 100% were obtained. The origin of the non-linear interaction was found ...