Superconductivity in the layered compound LixNbO2

TLDR: In this paper, the authors reported the discovery of a new class of superconductors, LixNbO2 with layered structures, which showed that at low applied magnetic fields, the magnetic susceptibility greatly decreases to diamagnetic values below 5.5 K.

Abstract: SEVERAL classes of copper oxide compounds are high-temperature superconductors1–3; the highest known transition temperature (Tc) is 122 K for Tl2Ba2Ca2Cu3O11 (ref. 4). Superconductivity has also been observed in oxides containing early transition metals, but the superconducting transition temperatures are substantially lower. (The highest known Tc for an early transition metal oxide is 13.7 K, for the spinel compound LiTi2O4 (ref. 5).) Whereas all of the copper oxide superconductors have very anisotropic structures, the superconducting oxides of early transition metals discovered up to now have three-dimensional structures. Here we report the discovery of a new class of superconductors, LixNbO2 with layered structures. At low applied magnetic fields, the magnetic susceptibility greatly decreases to diamagnetic values below 5.5 K for Li0.45NbO2 and below 5.5 K for Li0.45NbO2; this transition indicates the onset of superconductivity. In this first example of superconductivity in a layered early transition metal oxide, it is interesting to note that the layering has not increased Tc to new levels for early transition metal oxides.