GOALI: Magnetic Measurements to Characterize Chemistry and Structure in Nanoscale Doped Oxides

Colorado School Of Mines, Golden CO

Investigators

Abstract

NON-TECHNICAL DESCRIPTION: The addition of small amounts of metal atoms, or dopants, to ceramics frequently leads to remarkable property changes that can impact performance in applications such as fuel cells, gas separation, and photocatalysis. The reasons for these changes are believed to be related to the type and state of the dopant and its spatial distribution, all of which influence the material's response to a magnetic field. That response means every material exhibits a unique magnetic signature, and thus, magnetism may be used to understand the roles of dopants in ceramics. The PIs are benchmarking and modeling the magnetic signatures, with the ultimate goal to design new materials with exceptional properties. The collaboration with Quantum Design, a leading manufacturer of magnetometers, means innovations in metrology can be closely coupled with materials discoveries. Additionally, Quantum Design engages students through internships. As part of the project, students of the Colorado Center for Advanced Ceramics are organizing and running an annual on-campus conference in ceramics with participation from industry, university faculty, and members of the local community. The research has broad impact in many energy-related applications where challenges exist in understanding and controlling nanoscale phenomena. TECHNICAL DETAILS: This combined university-industry research project is pioneering magnetometry measurement techniques for nanoscale doped oxides and is utilizing these techniques to assess material behavior. The main scientific objective is to correlate the magnetic response of ceramic materials with nanoscale structural and compositional features such as size and distribution of second phases, solid solution arrangement including ion clustering and segregation, and dopant valence state. From the sensitivity of magnetometry to differentiate the various nanoscale structures, a particularly novel aspect is derived, namely that it is possible to study the initial stages of nucleation and growth of the metal dopant within the ceramic host during internal reduction. The behavior of dopants is being examined in two technologically important transition metal-doped oxide systems: yttria-stablized zirconia (YSZ) and yttria-doped barium zirconate-barium cerate perovskites (BZY-BCY). A suite of characterization tools, including a novel in situ Raman spectroscopy-magnetometry technique, enables kinetic and thermodynamic based descriptions of internal reduction and oxidation. The research lays the foundation to advance the state of nanoscale metrology for magnetometry. Graduate students are being engaged and trained in the potentially transformative magnetometry characterization tools under development.