Structural and Electrical Properties of CaBe0.75Si1.25
Ternary silicide compounds, Ca(BexSi1−x)2 (0.25 ⩽ x ⩽ 0.5) have been synthesized by a sealed tantalum ampoule method. When x = 0.375, a single phase of an AlB2‐type structure is observed, whereas some sub‐phases are observed when x ≠ 0.375 by X‐ray diffraction measurements. CaBe0.75Si1.25 (x = 0.375) is isostructural to the high‐temperature superconductor MgB2 (AlB2‐type structure) and similar to Ca(Al,Si)2. However, a detailed analysis reveals superlattice lines, indicating the ordering of Be and Si atoms. Whereas Ca(Al,Si)2 is a superconductor with a transition temperature TC of 7.7 K, the electrical resistivity of CaBe0.75Si1.25 shows metallic behavior above 4.2 K and is not a superconductor. In CaBe0.75Si1.25, the ordering of Be and Si atoms may play an important role in the suppression of superconductivity.