The development of orientation relations between sputtered YBa 2Cu 3O 7−δ and MgO substrates

Abstract

YBa 2Cu 3O 7−δ (YBCO) films grown by sputter deposition on bulk and buffer layer MgO substrates were examined using transmission electron microscopy (TEM). It was found that, although c -axis-up growth of YBCO is general for {001} MgO, unusual orientations with lower interfacial misfits are promoted if nucleated at c -in-plane YBCO which is itself preferentially found at ledges. However, c -up nucleation and growth of YBCO also occurs on [110} MgO. That the orientation relations are thus not entirely bulk controlled but equally not strongly affected by surface structure is discussed in relation to reduction of the MgO during growth.