Formation of Y xNd 1− xBa 2Cu 3O 7− δ (0≤ x≤0.9) superconductors from an undercooled melt via aero–acoustic levitation

Abstract

This paper presents the results of rapid solidification experiments performed on the copper oxide superconductors Y x Nd 1− x Ba 2Cu 3O 7− δ (0≤ x≤0.9). Spherical rare earth (RE) 123 specimens were levitated in O 2 using aero–acoustic levitation (AAL), melted with a laser, undercooled, and solidified. The peritectic transformation temperature for the reaction RE 2BaCuO 5+liquid→REBa 2Cu 3O 7− δ corresponding to the maximum recalescence temperature during solidification was determined. RE123 was formed directly from the melt for Y–Nd binary alloy compositions with Nd concentration greater than 20% (Y concentration less than 80%). A minimum in the peritectic transformation temperature for the Nd/Y123 system corresponding to a composition Y 0.3Nd 0.7123 was determined at 66 °C below the peritectic of pure Nd123.