Growth of rock-salt and spinel structured oxides on α-Al<inf>2</inf>O<inf>3</inf>, c-ZrO<inf>2</inf> and MgO

Pulsed-laser deposition has been used to grow thin films of the rock-salt and spinel structured oxides NiO, CoO and Co3O4 on single-crystal substrates of α-Al2O3, MgO and c-ZrO2. The resultantmicrostructures were characterized in plan-view by transmission electron microscopy and by low-voltage scanning electron microscopy. In all the depositions, the parameters could be controlled to grow predominantly single-crystal films. In the NiO/(0001)α-Al2O3 and CoO/(100)c-ZrO2 systems, {111}-oriented films were observed which were found to be twinned close to 60° and 90° about 〈111〉 respectively. Growth of cobalt oxide films on (100) MgO at 800 °C and 15 mTorr of oxygen produced {100}-oriented domains of Co3O4 meeting at antiphase boundaries. These observations and other recent studies re-emphasize the role of substrate crystallography in governing the orientation relationships in the overlayer.