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Enhancement of the upper critical field of Nb3Sn utilizing disorder introduced by ball milling the elements
L. D. Cooley, Y. F. Hu, A. R Moodenbaugh
Nb3Sn was prepared by milling Nb and Sn powder mixtures followed by limited reactions to restrict disorder recovery. Although disorder reduced the superconducting critical temperat…
Composition gradients and their effects on superconductivity in Al-doped MgB2
A. J. Zambano, A. R. Moodenbaugh, L. D. Cooley
(Abridged abstract) Alloyed MgB2 differs from pure forms in that diffusion is needed to distribute the alloying elements homogeneously. Williamson-Hall analyses of x-ray diffractio…
Inversion of two-band superconductivity at the critical electron doping of (Mg,Al)B
L. D. Cooley, A. J. Zambano, A. R. Moodenbaugh +3
Electron energy-loss spectroscopy (EELS) was combined with heat capacity measurements to follow the change of superconductivity with systematic Al doping of MgB. By using x-ray…
Formation of MgB2 at low temperatures by reaction of Mg with B6Si
L. D. Cooley, Kyongha Kang, R. Klie +3
Formation of MgB2 by reactions of Mg with B6Si and Mg with B were compared, the former also producing Mg2Si as a major product. Compared to the binary system, the ternary reactions…
Novel Synthesis and High Pressure Behavior of Na0.3CoO2 x 1.3 H2O and Related Phases
Sangmoon Park, Yongjae Lee, Arnie Moodenbaugh +1
We have prepared powder samples of NaxCoO2 x yH2O using a new synthesis route. Superconductivity was observed in Na0.3CoO2 x 1.3H2O between 4 and 5K as indicated by the magnetic su…
On the Doping and Temperature Dependence of the Mass Enhancement Observed in the Cuprate Bi2212
P. D. Johnson, T. Valla, A. Fedorov +9
High-resolution photoemission is used to study the electronic structure of the cuprate superconductor, Bi2212, as a function of hole doping and temperature. A kink observed in the…