Superconducting transition in electron-doped 12CaO•7Al2O3

It was reported that a mixed light metal oxide Compound, 12CaO center dot 7Al(2)O(3) (Cl2A7), which is known as a Constituent of aluminous cement, became a superconductor at an ambient pressure by the exclusive replacement of extra-framework oxygen ions in subnanometer-sized crystallographic cages with electrons. Temperature dependences of resistivity, magnetic susceptibility. and magnetic field dependent resistivity of single-crystals and thin films revealed superconducting transition at temperature (T-c) of similar to 0.4 K and a critical magnetic field of similar to 30 mT. T-c varies 0.2-0.4 K with the electron concentration. The interaction of the anionic electrons in the free space (cages) with the cationic framework may be responsible for the emergence of the superconducting state.