Metal Crystallites Grown in MgO Single Crystalline Films

Abstract

Composite films of magnesium oxide and metals (Au, Fe and Ti) are prepared by a simultaneous deposition technique. An important features of MgO-Au and MgO-Fe composite films is that metal is grown epitaxially and separately with the size of around 3 nm and 1 nm, respectively. The heat treatment for composite films of MgO-Fe at 500°C for 1 h and 1000°C for a few minutes bring about a grain growth of α-Fe up to 5 nm and a phase transformation of α-Fe to γ-Fe and quenched in to the room temperature, respectively. A strain of γ-Fe particles embedded is analysed through the distortion of the moire fringes. For MgO-Ti composite films, Ti grows as fine crystallites less than 1 nm with the structure of Ti_1-x0 with ordered vacancies. The heat treatment at 1000°C for a few minutes brings about the formation of Mg₂TiO₄ with the spinel structure.