Growth and Characterization of Reduced Dimensionality Superconductor-Related Phases by Molecular Beam Epitaxy
Abstract
This contract played a major role in enhancing the understanding and capabilities of reactive molecular beam epitaxy (MBE) to assemble oxide heterostructures with unit cell layering precision. The specific compounds grown under its support included (Ba,K)BiO3, YBa2Cu3 O(7-delta), SrTiO3, PbTiO3, Bi4Ti3O12, and superlattices of these compounds. Several of these materials had never before been grown by MBE and in addition to achieving an enhanced understanding of the underlying growth mechanisms of these compounds, the structural and electrical properties of the thin films and superlattices surpass those achieved by other thin film techniques. For example, our MBE-grown Bi4Ti3O12 films have the lowest RBS minimum channeling yield (chi min) and exhibit remanent polarization values of approx. 3 microC/sq cm along the c-axis which is approximately the value observed in this same measurement direction for bulk single crystals (approx. 4 microC/sq cm) and significantly exceeds the highest value previously reported for epitaxial films of this material (i.e., 1 microC/sq cm reported by R. Ramesh et al., Science 252 (1991) 944). We have identified adsorption-controlled growth conditions, analogous to those used for the preparation of III-V and II-VI semiconductors by MBE, for the synthesis of PbTiO3 and Bi4Ti3O12 and assessed the thermodynamics of why this occurs. In addition this contract supported work related to the integration of oxides with silicon. This contract supported two (U.S. citizen) graduate students, both of whom completed their M.S.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1998
- Accession Number
- ADA340914
Entities
People
- Darrell G. Schlom
Organizations
- Pennsylvania State University