Thin superconducting oxide films

Studies of superconductivity in thin films of La-Sr-Cu-O and Y-Ba-Cu-O have resulted in samples completely superconducting at 87 K and with onsets as high as 97 K. The high-$T_c$ materials show a strong Meissner effect which agrees with the temperature dependence of the resistance. Critical current densities in excess of 300 A/${\mathrm{cm}}^2$ have been measured close to $T_c$ in the Y-based materials.