Magnetic and Electronic Properties of Single-Crystalline BaCoSO

Doped BaCoSO was recently predicted to be a high-temperature superconductor in a new class based on Co and Ni. Using a Co-S self-flux method, we synthesized single crystals of the antiferromagnetic insulator BaCoSO. Our magnetic and specific heat measurements and neutron diffraction provide details of its magnetic anisotropy and order. Its band gap was determined to be about 1.3 eV by our measurements of its photoemission spectrum and infrared optical conductivity. Our results can pave the way to exploring the predicted superconductivity in this Co-based material.