Effects of surface treatment of single-crystal MgO substrates on the growth and properties of YBa/sub 2/Cu3O/sub 7-y/ films

The preferred orientation and the inplane alignment of YBa/sub 2/Cu/sub 3/O/sub 7-y/ (YBCO) thin films deposited on MgO [100] substrates by on-axis DC magnetron sputtering have been investigated. The deposition temperature highly influences the preferred orientation of films. Films were oriented with the a-axis perpendicular to the substrates for low temperature depositions and with the c-axis for high temperature depositions. In the c-axis oriented films, there exist YBCO grains with the a(or b)-axis parallel to MgO [100] and 4-5/spl deg/ -rotated ones. 45/spl deg/ -rotated grains exclusively grow under the conditions of higher temperatures and on the substrates treated by acid-etching. The volume ratio between both types of YBCO grains is strongly connected with critical current density, even in the c-axis oriented films.<>