Co-appearance of superconductivity and ferromagnetism in a CaRuO nanofilm crystal.

By tuning the physical and chemical pressures of layered perovskite materials we can realize the quantum states of both superconductors and insulators. By reducing the thickness of a layered crystal to a nanometer level, a nanofilm crystal can provide novel quantum states that have not previously been found in bulk crystals. Here we report the realization of high-temperature superconductivity in CaRuO nanofilm single crystals.