A. Krol, C.J. Sher, et al.
Surface Science
We have studied the dependence of the magnetic properties of pellets of nominal composition YBa2Cu3O7-x on variations in preparation conditions. We find that rapid quenching of the pellets from annealing temperatures greater than 500-600°C causes the formation of significant amounts of secondary phases. Two of these phases, Y2BaCuO5 and BaCuO2, have magnetic moments of approximately 1.8 B per Cu atom. We find that Y2BaCuO5 orders antiferromagnetically below 30 K whereas BaCuO2 is paramagnetic down to at least 6 K. Eliminating these secondary phases by optimizing the processing conditions gives single-phase material (> 99.8% by mass) for which the magnetic susceptibility above the superconducting transition temperature is nearly independent of temperature. The magnitude of this susceptibility, after correction for ioncore diamagnetism, is enhanced by a factor of approximately 2 over the Pauli susceptibility estimated from the band-structure density of states, indicating the importance of electron-electron correlation effects. © 1988 The American Physical Society.
A. Krol, C.J. Sher, et al.
Surface Science
T.N. Morgan
Semiconductor Science and Technology
J.V. Harzer, B. Hillebrands, et al.
Journal of Magnetism and Magnetic Materials
Sang-Min Park, Mark P. Stoykovich, et al.
Advanced Materials