Novel Phenomena in Single-Crystal Oxides

University Of Kentucky Research Foundation, Lexington KY

Investigators

Abstract

Technical Abstract It is widely recognized that whoever discovers and controls the optimized synthesis of novel materials generally controls the investigation of their often unique properties and, ultimately, their successful integration into advanced technologies. The proposed research is to build upon our recent success on studies on single crystals of 4d or 5d-electron-based materials and emphasize (1) the synthesis and characterization of novel transition metal oxides in bulk-single-crystal form and (2) a rigorous search for new materials. The novelty of these materials is highlighted by our recent discoveries, such as orbitally-driven colossal magnetoresistance (CMR) attained by avoiding a ferromagnetic state, and a novel spin valve effect in bulk single crystals, a delicate quantum phenomenon that depends upon precision deposition and nanoscale patterning of artificial thin-film heterostructures whose quality and performance are difficult to control. While these discoveries open new avenues for understanding the underlying physics of spintronics, and fully realizing the potential in practical devices, new physics unique to these materials, which are largely driven by spin-orbit coupling, continues to emerge, and better understanding this physics will surely lead to new discoveries. It is this new physics and possible new discoveries we seek to pursue. The transfer of technical expertise will be achieved via direct integration of the graduate students and post-docs into ongoing research efforts with a goal of professional journal publication of results. The proposed program will also constitute a key thrust within the newly established multidisciplinary Center for Advanced Materials. This association will help nurture interdisciplinary expertise that will stimulate collaborative research, and generate synergies that will attract new students who are the future human capital in technologies driving the economy. Non-Technical abstract Condensed matter physics addresses identification of novel, fundamental properties of solids and liquids that have generated a remarkable number of cutting-edge technologies in recent decades. It is widely recognized that whoever discovers and controls the optimized synthesis of novel materials generally controls the investigation of their often unique properties and, ultimately, their successful integration into advanced technologies. Unfortunately, U.S. leadership in materials research has seriously eroded in recent years due to a growing shortage of scientists who possess skills in both the synthesis and characterization of new materials. The current situation presents an urgent national challenge that could ultimately undermine our economic competitiveness if left unaddressed. The proposed research is to build upon our recent success on new materials studies and emphasize the synthesis and characterization of novel materials in bulk-single-crystal form and a rigorous search for new materials. The novelty of these materials is highlighted by our recent discoveries, such as a novel spin valve effect in bulk single crystals, a delicate quantum phenomenon that depends upon precision deposition and nanoscale patterning of artificial thin-film heterostructures whose quality and performance are difficult to control. Spin valves or more generally spintronic (magnetoelectronic) materials not only have technological potential as magnetic field sensors and read-heads for computer hard drives, but also present fundamental challenges to the theory of magnetotransport in solids. These are among the most intensively studied phenomena in materials physics and engineering due to their enormous potential impact on a $100-billion-per-year electronics industry. It is the technological potential and the intellectual challenges these materials present that we seek to pursue. The transfer of technical expertise will be achieved via direct integration of the graduate students and post-docs into ongoing research efforts with a goal of professional journal publication of results. The proposed program will also constitute a key thrust within the newly established multidisciplinary Center for Advanced Materials funded by the NSF EPSCoR RII. This association will help nurture interdisciplinary expertise that will stimulate collaborative research, and generate synergies that will attract new students who are the future human capital in technologies driving the economy.