EPITAXIAL-GROWTH AND PROPERTIES OF (CO3) STABILIZED BACUO2 SUPERCONDUCTING THIN-FILMS

We report on the epitaxial growth of BaCuO2 infinite layer (stabilised with CO3 groups) thin films by rf magnetron sputtering on (100) SrTiO 3 and (100) LaAlO3. Excellent (001) films with c-4 Angstrom are obtain ed at 540 degrees C in a sputtering atmosphere of 1-10 mTorr of Ar+O-2 with some addition of CO Off axis x-ray analysis reveal perfect in pl ane ordering and a tetragonal structure with a=b-3.96 Angstrom. For th ese deposition conditions the resistivity at room temperature is of th e order of several Omega cm and exhibits a strong semiconductor-like b ehaviour. When the deposition temperature is increased to 660 degrees C, a supercell along the c axis appears with a period of about 8 Angst rom. After an in-situ annealing of these films in 7 Torr of oxygen at 500 degrees C, rho(300K) falls to 800 mu Omega cm. The resistance vers us temperature curve reveals then a metallic behaviour and a supercond ucting transitions with onsets between 10-40K.