Growth of YBa2Cu3O7 thin films on MgO: The effect of substrate preparation

Abstract

We discuss the results of a study of the effect of substrate preparation on the microstructure and superconductive properties of YBa2Cu3O7 thin films formed by laser ablation on (001) MgO substrates. Thermal annealing of the substrates is found to be highly effective in producing at fairly low growth temperatures (670 °C), epitaxial, c-axis normal films with good superconductive properties. Alternative surface treatments result in the formation of large angle tilt boundaries and inferior superconductive properties.

Growth of Laser Ablated YBa2Cu3O7Thin Films Epitaxied on (100)MgO: Influence of In-Plane Misorientations on Low and High Frequency Properties

“…Indeed, Moeckly et al [11] have previously reported the influence on in-plane orientation of various substrate's surface treatment (chemical or mechanical polishing, high temperature annealing) but we could not reproduce their results. Specific treatments of substrates have been reported and will be discussed in a following section.…”

“…Indeed, the experiments of Moeckly et al [11] have suggested such an effect: from pole figures analyses, they have reported that films grown on chemically polished substrates gave a mixture of several in-plane orientations whereas mechanically polished substrates and, even more clearly, annealed substrates, tend to give unique c┴0 orientation. This result could be related to the formation, at the substrate surface, of steps favorable to a lateral growth, as shown by a very recent AFM comparative study of YBCO fllms grown on either untreated or 12000C annealed (100)MgO substrates [21].…”

Use of a 3C–SiC Buffer Layer and Vicinal Substrates for the Heteroepitaxial Growth of MgO Films on Si(001)

“…Numerous such studies, on an atomic scale, have been carried out. Stranski±Krastanov, Volmer±Weber, and Frank±van de Merwe growth are well known and have been studied extensively, [1,2] particularly the lattice constants of the materials involved and their surface and interface formation energies. Also, diffusion limited aggregation (DLA) is not only known in the growth of snowflakes, but also occurs on single crystal surfaces however, a nucleation site (such as a defect) is necessary for their development.…”

“…It is also a thermally stable and highly ionic insulating crystalline solid with a rock salt structure. MgO single crystals have been used as substrates for oxide materials such as high-temperature superconductors, [1,2] and ferroelectric materials. [3,4] Recently, MgO films have been utilized as a protective layer for the electrodes in plasma display panels (PDPs).…”

Texture Investigations on High Temperature Superconductors

“…A more comprehensive description of the texture is achieved by pole figures (Knorr, 1989); Osamura, 1989;Moeckly, 1990, Aksenova, 1992Itskovich, 1994). If in addition to a (001)-pole figure also a pole figure of a pyramid plane is determined it can be decided whether the (a,b)-axes are parallel.…”