Preparation of a -axis oriented YBa ₂ Cu ₃ O _x thin films

The a-axis oriented YBa2Cu3Ox (YBCO) thin films could be grown on (100) SrTiO3 (STO) substrates with STO buffer layers by dc and rf magnetron sputtering either by lowering the deposition temperature, or by using a self-template technique. For the latter, the resistivity of the thin film at 290 K along the substrate [001] direction is about four times larger than that in the [010] direction. The zero resistance temperatures Tc0 are 89 K in both directions. So high quality a-axis oriented YBCO thin films can be prepared by the self-template technique. Also the Tc0 increase monotonously with the reduction of the thickness of the YBCO seed layer.