Abstract
The composition, crystal structure and superconducting properties of HgBaCuO and HgBaCaCuO superconductors were investigated. Samples with various nominal compositions were prepared from the mono-oxides of Hg, Ba, Ca and Cu using various sintering processes. The samples were examined by X-ray powder diffraction and energy dispersive X-ray analysis (EDX). The HgBaCuO samples were found to be nearly single phases of HgBa2CuO4+δ (Hg-1201), but the HgBa CaCuO samples contained HgBa2Ca2Cu3O8+δ (Hg-1223), HgBa2CaCu2O6+δ (Hg-1212) and other phases. The fraction of the higher-Tc phase in the HgBaCaCuO sample varied in accordance with the nominal composition. High-resolution transmission electron microscopic (HRTEM) studies revealed the existence of Hg-1201 (tetragonal cell with a=3.85 and c=9.5 A ̊), Hg-1212 (c=12.6 A ̊). and Hg-1223 structures (c=15.7 A ̊). Most of the HgBaCuO samples exhibit 95 K-classs superconductivity, and the Hg BaCaCuO samples showed 130 K-class superconductivity. The highest Meissner onset temperature, Tcm determined from DC susceptibility was 134 K. The same sample showed superconductivity with a ≈ 16% diamagnetic volume fraction at 5 K.
| Original language | English |
|---|---|
| Pages (from-to) | 250-256 |
| Number of pages | 7 |
| Journal | Physica C: Superconductivity and its applications |
| Volume | 216 |
| Issue number | 3-4 |
| DOIs | |
| Publication status | Published - 1993 Nov 1 |
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering