High‐Temperature Electrical Properties of the Bi_2.1Sr_1.9(Ca_1–xY_x)Cu₂O_y Solid Solution

By a combination of conventional physical property measurements and high‐temperature electrical property studies, the solid solution limit, transport parameters, and potential defect regimes of the Bi_2.1Sr_1.9(Ca_{1 ‐ x}Y_x)Cu₂O_y solid solution were established. A continuous solid solution extends to x= 0.7 or 0.8. The electrical properties indicate that the product of the hole density‐of‐states and mobility for semiconducting compositions is approximately an order of magnitude smaller than for the other p‐type superconducting cuprates. A pronounced drop in hole concentration accompanies the tetragonal‐to‐orthorhombic transition at x= 0.5, whereafter superconductivity disappears. The electrical properties also indicate that a composition x change occurred reversibly below 1100°C.