Current status of development of high-Tc superconducting thin films

Superconducting properties of LnBaCuO(Ln: Ho, Er, Y), BiSrCaCuO and TlBaCaCuO thin films prepared by rf magnetron sputtering, using a MgO single crystal substrate, were examined. The critical current densities of epitaxially grown single crystalline LnBaCuO thin films were in excess of 3×106 A/cm2 at 77.3K. In the polycrystalline BiSrCaCuO and TlBaCaCuO thin films around the cation ratio 2:2:2:3, the critical current density at 77.3K were 3.4×106 A/cm2 and 3.2×106 A/cm2, respectively.