1. Preparation and characterization of Y1−xPrxBa2Cu4O8
- Author
-
B. Lippold, M. Krötzsch, J. Herrmann, U.-C. Boehnke, and F. Schlenkrich
- Subjects
Superconductivity ,Valence (chemistry) ,Materials science ,Magnetic moment ,Transition temperature ,Energy Engineering and Power Technology ,Ambient oxygen ,Condensed Matter Physics ,Magnetic susceptibility ,Electronic, Optical and Magnetic Materials ,law.invention ,Crystallography ,law ,Electrical and Electronic Engineering ,Crystallization - Abstract
In comparison to the Y 1− x Pr x Ba 2 Cu 3 O 7−δ (Y/Pr-123) system the influence of the substitution of Pr for Y on the structural and superconducting properties of the Y 1− x Pr x Ba 2 Cu 4 O 8 (Y/Pr-124) system was investigated. Among the different reaction procedures for the synthesis at ambient oxygen pressure a technique involving the crystallization from the quenched melt was employed for the first time. In analogy to the Y/Pr-123 system the Pr substitution leads to an increase of the unit-cell parameters and to a successive suppression of superconductivity in Y/Pr-124 with a critical Pr concentration x cr of 0.75 which is higher than that of 0.56 for Y/Pr-123. The normal-state behavior of the Y/Pr-124 samples could be described by a Curie-Weiβ law, yielding effective Pr moments of about 2.5μ B that correspond to a Pr valence of 4+. Different from the Y/Pr-123 system, the Curie-Weiβ temperature θ was found to be positive for the superconducting and negative for the normal samples, whereas in Y/Pr-123 θ was always negative.
- Published
- 1994
- Full Text
- View/download PDF