Electrical properties of high T/sub c/ superconductors under high pressures
Abstract
Pressure has played a significant role in the recent developments of high transition temperature (T sub c) superconductors. This document reports electrical resistance measurements in these new superconductors at pressures up to 16 GPa. Our measurements were performed on single-phase but polycrystalline samples of La(sub 1.85)Ba(sub 0.15)CuO4, La(sub 1.85)Sr(sub 0.15)CuO4 and YBa3Cu4O(sub 7.5). The samples were typically small fragments of about 200 microns across obtained by crushing larger pellets which have been characterized by X-ray, resistivity and magnetic susceptibility measurements at ambient pressure. Quasi-hydrostatic pressure was applied with a diamond anvil high pressure cell. The sample was surrounded by CaSO4 powder as the pressure medium and the pressure was determined by the standard ruby fluorescence technique. Diamond anvils of three different sizes have been utilized to cover these three pressure ranges: 0 to 5 GPa, 2 to 10 GPa, and 3 to 20 GPa. The resistance of the sample was determined by a quasi-four-probe technique via two loops of copper wires. Electrical contact between the copper wire and the sample was achieved by pressure.
- Publication:
-
Presented at the Workshop on Novel Mechanisms for Superconductivity
- Pub Date:
- June 1987
- Bibcode:
- 1987nmsc.work.....E
- Keywords:
-
- Electrical Properties;
- High Pressure;
- High Temperature Superconductors;
- Polycrystals;
- Superconductivity;
- Barium Oxides;
- Lanthanum Oxides;
- Pressure Dependence;
- Transition Temperature;
- Yttrium Oxides;
- Solid-State Physics