2 DISTINCT STRUCTURAL PHASES IN SR3-XCAXRU2OY

Non-cuprate layered perovskite Sr2RuO4, which is an analogue of (La,Sr )(2) CuO4, exhibits superconductivity below T-c approximate to 1K. We have synthesized a new system Sr3-xCaxRu2Oy, and found the solubility of Ca to be at least as much as x = 2. These samples are not supercond uctive down to 2K but magnetically ordered. The x dependence of the la ttice parameters and that of T-mag clearly indicate that there are at least two distinct structural phases in Sr3-xCaxRu2Oy.