Materials World Network: Designed Preparation, Characterization, Magnetic Properties and Quantum Chemical Calculations of New Complex Itinerant Magnets, Ti(8-x)M(3+x)Ru(18-y)Rh(y)B

Iowa State University, Ames IA

Investigators

Abstract

This project combines experiment and theory towards the designed preparation and subsequent characterization and thorough understanding of new intermetallic ferromagnets and antiferromagnets. It is based on collaboration between Iowa State University and RWTH Aachen in Germany. The primary concept involves using a complex 4d metal-boride framework with magnetic 3d elements, e.g., Cr, Mn, Fe, Co and Ni, inserted in voids to create magnetic structures with potentially low-dimensional character. The metal-boride framework provides a structurally strong and electronically robust network for insertion of magnetic metals into channels. Furthermore, the metal-boride structure is intrinsically metallic, which provides a mechanism for magnetic exchange between adjacent magnetic metal atoms via the spins on the conduction electrons. Specifically, these materials are studied by X-ray and neutron diffraction as well as magnetization experiments to determine atomic and magnetic structures. Theoretical determination of the electronic structures on various models of these structures provides feedback toward further synthetic efforts of atomic substitutions to create new compounds with targeted magnetic behavior. At present, chemists and materials scientists have no general, yet simple, rules for targeting and tailoring ferromagnetic, intermetallics compounds, i.e., metallic compounds with permanent magnetic behaviour. This effort allows chemists to study an evolution of magnetic behaviour within a single structural family to identify trends in magnetic behavior as various chemical and physical parameters change in systematic ways. A project such as this, that combines experiment and theory for condensed matter systems, provides students a truly interdisciplinary problem - these students learn how different scientific subjects and models impact other scientific areas. The student participants in this project in Aachen, Germany and Ames, Iowa have opportunities for exchange, and they learn both experimental and theoretical components of research in solid-state chemistry. Furthermore, through this systematic study of a structural family, a set of rules will be generated for targeting metallic, permanent magnets, which have numerous technological applications. The real challenge will be to identify the temperature range where such targeted materials will show permanent magnetic behavior. In summary, this effort represents a strong, synergistic coupling of experiment and theory that targets new magnetic materials, and may lead to new materials with unusual bulk magnetic properties due to the potential one-dimensional character of the magnetic exchange.