CAREER: Opening the Door to Emerging Functional Multicomponent Oxides via a Novel Crystal Growth Approach

University Of Tennessee Knoxville, Knoxville TN

Investigators

Abstract

Part 1: Non-Technical Summary With support from the Solid State and Materials Chemistry program in the Division of Materials Research this research project investigates how gravity can be exploited to grow new and interesting crystal structures. Using a crystal growth technique that is unique in a U.S. academic institution, Prof. Zhuravleva prepares novel materials with functional properties that could facilitate clean energy, reduce the cost of lighting, improve medical devices and imaging, and lead to new discoveries in fundamental physics. Specifically, this project examines how gravity-controlled melt flow can be used to engineer uniformly distributed rare earth ions into crystals, which is critical in order to unlock the potential of these materials. Understanding how the dynamics of crystal formation under microgravity lead to stable formations provides foundational knowledge for future materials engineering research. This project is complimented by an outreach and education program that integrates high-temperature crystal growth under microgravity with new, hands-on curricula to engage underrepresented groups in science and engineering and encourage the next generation of research professionals. Part 2: Technical Summary This project, supported by the Solid State and Materials Chemistry program in the Division of Materials Research, addresses the need for novel routes for synthesis of unconventional materials. It aims to enable the full scientific potential of single-phase multicomponent equiatomic rare earth oxides as a new class of functional materials. These oxides have not been explored nearly as extensively as high-entropy metallic alloys and until now have existed only as polycrystalline ceramics. A revolutionary method, micro-pulling-down technique, is used for the first time to demonstrate crystal growth and investigate mechanisms that govern gravity-controlled melt convection during directional crystallization of such complex systems. The project exploits the interplay between the convective and diffusive melt flow patterns in order to enhance melt mixing near the growth interface and achieve stable growth conditions. As a result, phase stability and homogeneous cation distribution in the grown crystals leads to novel phenomena and properties for applications in clean energy, lighting, medical, national security and fundamental physics research that may surpass functionality of traditional one-component compounds. A large number of possible combinations opens a pathway to compositional feasibility of a large number of complex systems. Additionally, the micro-pulling-down method as a tool for materials discovery and synthesis is introduced to the US academic community for both research and education through this research project. Availability of modern crystal growth techniques improves the national competitiveness in materials research and provide opportunities for educating and training future crystal growth scientists. The latter aspect is accomplished by an outreach and education program that integrates high-temperature crystal growth under microgravity with new, hands-on curricula to engage underrepresented groups in science and engineering and encourage the next generation of research professionals. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.