Abstract
The temperature dependence of the resistivity along the c axis and in the a-b plane of layered has been measured on a single crystal under hydrostatic pressures. The monoclinic metallic (LTM) phase stable at is suppressed under a pressure it has a nearly isotropic conductivity. Pressure induces an insulator-metal (IM) transition at within the tetragonal phase. A change from a nearly isotropic conduction to a highly anisotropic conduction is associated with the IM transition. Isotropic conduction in the LTM phase is consistent with its crystallographic structure; the IM transition in the tetragonal phase has been interpreted to be due to a high-spin to low-spin transition of Co(II) ions. The resistivity and thermal conductivity of the LTM metallic phase are typical of those of a normal metal.
- Received 1 March 2001
DOI:https://doi.org/10.1103/PhysRevB.64.140101
©2001 American Physical Society