Abstract
Crystals of orthorhombic, superconducting have been prepared. They are twinned in the nearly tetragonal plane. The resistivity and Hall effect have been measured in the normal state in the plane, the highly conducting plane of the Cu-O layers. We find that the resistivity in the plane, measured with currents exclusively in the plane, is strictly linear in temperature from room temperature down to the fluctuation regime near the superconducting transition. This result confirms previous less direct measurements in which the currents flowed in the much more resistive direction as well. We find the Hall constant for the magnetic field parallel to and the currents in the plane, to be type and inversely proportional to temperature. This latter behavior is extremely unusual and unexplained, but similar to that found in polycrystalline material. It is in contrast to our previous result for the magnetic field in the plane. In that case, the Hall constant is type and nearly temperature independent. Both the Hall effect and the resistivity demonstrate the extremely anisotropic nature of this system.
- Received 7 March 1988
DOI:https://doi.org/10.1103/PhysRevB.38.2918
©1988 American Physical Society