Faculty Awards for Women Scientists and Engineers

点击翻译按钮获取中文摘要

The NSF Faculty Awards for Women Scientists and Engineers recognizes the high quality of the awardee's record in teaching and scholarship, as well as potential for continued significant contributions to scientific research, the academic profession, and the education of future scientists and engineers. Dr. Stacy's research focuses on developing innovative methods for the synthesis of new classes of superconducting oxides. The discovery of superconductivity in copper oxides above 77 K has captured our imagination with the potential to revolutionize technology; scientists anticipate that with these materials it will be possible to provide cheaper power, high field magnets for medical applications, computers with higher speeds, and ultra-sensitive detectors. Unfortunately, all of the known high temperature superconductors are difficult to process into forms suitable for these applications. Because processing is intimately related to applicability, it is essential that materials and synthetic methods be developed simultaneously with the hope of finding new classes of superconductors which are easier to process. The goal of this research is to search for new high temperature superconductors by developing methods for the synthesis of quaternary metal oxides. We have discovered that fused hydroxides are ideal for the preparation of cuprate superconductors at temperatures as low as 350 degrees Centigrade. Among the many advantages of this new route are selective precipitation of the products at relatively low temperatures, and simplicity in the formation of solid oxide materials. Moreover, over a dozen new cuprates and bismuthates have been crystallized by varying the solution conditions, such as concentrations of reactants, acidity, and temperature, and by varying the atmosphere over the melt. The characterization of these new compounds has made it possible to gain a better understanding of the electronic properties of oxides. It is planned to continue a systematic investigation of the use of hydroxide melts for the synthesis of new oxides, extend the work on cuprates and bismuthates to early transition metal oxides, and search for new oxides containing niobium. A wide range of hydroxides and conditions will be explored. It is believed that as the chemistry of this synthetic method is elucidated, it will be possible to select conditions that favor particular structural features in the solids that are crystallized. The structures of all new compounds will be determined by X-ray diffractions methods. The magnetic and electronic properties will be measured to test for superconductivity, and to gain a more thorough understanding of structure-property relationships.