Synthetic Multiferroic Oxides Prepared by Gel Collection

Cuny City College, New York NY

Investigators

Abstract

NON-TECHNICAL DESCRIPTION: Multiferroics represent an outstanding 21st century challenge toward next generation electronics, due to the exciting prospect of combining magnetism and electrical polarization in a single compound with true spin-charge coupling. Combining both properties is very exciting scientifically in terms of the devices that might ultimately be designed, in logic circuits or spintronics, furthering the quest for the ultimate memory device for computing. The challenge is to find new materials that can show spin-charge coupling of meaningful magnitude, closer to room temperature. This project applies an innovative green chemical synthetic technique developed by the researcher, Gel Collection, to the discovery of novel oxide compounds that exhibit multiferroic properties, synthetic multiferroic oxides. This project is experimental in nature, supported by scientific theory; new material discoveries may spark more theory. The project trains graduate students in materials chemistry and nanotechnology, through synthesis, structure characterization and in the measurement, interpretation and crossover of electricity and magnetism. Select undergraduate students in the chemistry program on-campus are also trained. The project promotes diversity and broadens participation of underrepresented groups in materials science, through a peer-learning program between the City College of New York and a local high school, both minority-serving institutions. The project includes an elementary school visitation program within the New York City public school system, with introductory exploratory kits in STEM aimed at grades K through 5. TECHNICAL DETAILS: Progress in multiferroics has been limited by physical restrictions on the co-existence of magnetic or electrical polarization vector fields in a single compound, and the magnitude of magnetoelectric coupling. Presently, there are real opportunities, theoretically and experimentally, for placing lower constraints on this coexistence. The impact of this research is the deployment of a low temperature chemical synthesis technique effective for making new materials that are multiferroic and/or high dielectric in nature. The project relies on a solution processing approach, based on precursor coordination chemistry, sol-gel and nanochemistry that offers routes to new complex oxides of previously unexplored compositions and stoichiometry. The procedure is considered green, due to the complete consumption of reactant precursors and use of non-toxic solvents, which are recycled. The project researchers prepare and characterize novel complex oxides, such as Ba-Ti-Mn-O hollandites, study the structure-property relationship through a combination of structural (X-ray crystallography, electron microscopy, companion analytics), spectroscopic (Infra-red, Raman, X-ray photoelectron) and ferroic (impedance, magnetic, ferroelectric) characterization techniques. Seeking and detecting potential magnetoelectric coupling in novel multiferroic complex oxides is an underlying, long term challenge, with many important research and education goals along the way.