Physical properties of the novel layered cobalt oxyphosphide Sr ₂ScCoPO₃

A novel layered cobalt oxyphosphide Sr₂ScCoPO₃ crystallizes in a layered structure which represents an alternative stack of anti-fluorite type Co₂P₂ layer and K₂NiF ₄ type Sr₄Sc₂O₆ layer. This material has a similar structure to that of Sr₂ScFePO₃ which exhibits superconductivity below 17 K The resistivity of Sr ₂ScCoPO₃ is 4.5 mΩcm at room temperature and decreases with decreasing temperature. The thermoelectric power of Sr ₂ScCoPO₃ is -12 μV/K at room temperature and it decreases with decreasing temperature and rapidly increases below 50 K Provided the generalized Hikes formula, the S of Sr₂ScCoPO₃ is estimated to be -60 μV/K at high temperature region. This relative high value suggests that Sr₂ScCoPO₃ is a promising high performance thermoelectric material.