Browsing by Author "Jorgensen, JD"

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    Atomic substitution and carbon isotope effect in superconducting MgCNi 3
    (AIP Publishing, 2006-09-07) Klimczuk, T; Gupta, V; Avdeev, M; Jorgensen, JD; Cava, RJ
    The superconductor MgCNi3 has been chemically doped by substitution of Ru and Fe for Ni and B for C. Neither ferromagnetism nor increasing TC is observed, suggesting that MgCNi3 has optimal superconducting properties at its intrinsic composition and electron count The effect of Carbon isotope substitution on Tc is reported: the carbon isotope effect coefficient is αc = 0.54±0.03. This indicates that carbon‐based phonons play a critical role in the superconductivity. © 2006 American Institute of Physics.
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    Incomplete and irreversible high-pressure induced ferroelectric to antiferroelectric phase transition of PZT95/5(2Nb) studied by in-situ neutron diffraction
    (The Bragg Institute, Australian Nuclear Science and Technology Organisation, 2005-11-27) Avdeev, M; Jorgensen, JD; Short, SM; Morosin, B; Venturini, EL; Yang, P; Samara, GA
    Zr-rich lead zirconate titanate ceramic and powder samples with composition near Pb0.99(Zr0.95Ti0.05)0.98Nb0.02O3 [PZT95/5(2Nb)] have been studied in the range of hydrostatic pressure (0—6.2 kbar) and temperature (10 295 K) by time-of-flight neutron powder diffraction and dielectric measurements. The transformation from the ferroelectric R30 phase FR(LT) to the antiferroelectric Pbam phase is incomplete: even at our highest pressure of 6.2 kbar, §wt.% of the sample remains in the FR(LT) phase. On pressure release to i bar at 295 K, only 26% of the FR(LT) phase is recovered. © The Authors