9403895 Shelton Technical abstract: This experimental research program focuses on multinary oxides that display a combination of properties including high-temperature superconductivity, long-range magnetic order, valence fluctuations and anisotropy order parameters. To determine the intrinsic physical properties, the research emphasizes experiments on high quality single crystals. Three systems form the core of these studies; namely rare-earth barium cuprates, rare- earth barium niobates, and rare-earth strontium niobates. To insure consistency and uniformity in interpreting the experimental results, a great variety of complimentary experiments will be performed on the single crystals. Non-technical abstract: This experimental research program focuses on three families of materiald that show great promise for technological applications as well as probing the exciting state of high-temperature superconductivity. Due to the intrinsic complexity of these multi-component materials, great emphasis is place on using the highest quality crystals for this study. Goals with practical components include: elemental substitutions to stabilize the superconducting state against fluctuations in operating environment of the superconducting device; discovery and characterization of materials from the same family suitable as insulating analogs in device fabrication. ***