Single crystals of Sr2HoRu1−xCuxO6 (with x = 0–0.2), measuring 2–3 mm across have been grown from PbO–PbF2 based solutions in the temperature range of 1250–1150 °C. The crystals exhibit octahedral morphology and belong to the monoclinic space group P21/n. While Sr2HoRuO6 is found to be antiferromagnetic with weak ferromagnetism below 30 K, the solid solutions containing Cu exhibit a diamagnetic transition at 31 K which increases in magnitude and temperature with increasing Cu. Through a correlation of magnetic and calorimetric properties, these crystals are concluded to be spin-glass superconductors.
