A new family of superconductors were observed in the (Pb0.5Hg0.5)Sr2(Ca1-xYx )Cu2O7-δ system for the composition range 0.5 ≤ x ≤ 0.2, with a maximum Tc of 90 K (at x = 0.3) as determined by electrical resistance and magnetization measurements. We have investigated the crystal structure across the entire composition range by X-ray diffraction, by which we identify the phase responsible for the superconductivity to be similar to that of (Pb,Cu)Sr2CaCu2O7 (the so-called Pb-based 1212 phase) with a space group of P4/mmm and lattice constants of a ranging from 3.8159(6) Å for x = 0.5 to 3.8082(4) Å for x = 0.2, and c ranging from 11.950(2) Å for x = 0.5 to 12.022(2) Å for x = 0.2. Moreover, the chemical composition of one sample in the series having nominal composition (Pb0.5Hg0.5)Sr2(Ca0.5Y0 .5)Cu2O7-δ(x = 0.5) was determined to be [Pb0.6Hg0.2Cu0.2]Sr2.0[Ca 0.42Y0.51Hg0.07] Cu2O7- δ by energy-dispersive spectrometry.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry