Physical properties of the novel layered cobalt oxyphosphide Sr2ScCoPO3

Abstract

A novel layered cobalt oxyphosphide Sr2ScCoPO3 crystallizes in a layered structure which represents an alternative stack of anti-fluorite type Co2P2 layer and K2NiF4 type Sr4Sc2O6 layer. This material has a similar structure to that of Sr2ScFePO3 which exhibits superconductivity below 17 K The resistivity of Sr2ScCoPO3 is 4.5 mΩcm at room temperature and decreases with decreasing temperature. The thermoelectric power of Sr2ScCoPO3 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.