1. Correlated Phenomena in Atomically Arranged Transition Metal Perovskites Nugget ID: Intrinsic properties of materials depend on chemical composition and structural arrangement of constituent atoms. A multi-national research team (European partners: Dr. A. Maignan, Laboratoire Crismat-ISMRA, Caen, France; Prof. J. Paul Attfield, University of Edinburgh, UK; Dr. A. Wisniewski, Institute of Physics, Warsaw, Poland; Dr. K. Rogacki, Institute of Low Temperature and Structural Research, Wroclaw, Poland) headed by Professor Bogdan Dabrowski has demonstrated that it is possible to design, produce, and investigate a wide range of novel perovskite compounds ABO3-d exhibiting enhanced magnetic, magneto- resistive, conducting, thermoelectric, and other properties useful for practical applications. This has been accomplished by accurately measuring distances and coordination of the alkaline and rare earth’s and transition-metal atoms to oxygen as a function of temperature and oxygen content, and using this information to derive understanding of the factors affecting chemical stability and properties. By tuning oxygen content of new phases during synthesis the local atomic order has been adjusted, and the electronic properties studied as a function of controlled disorder. The in-depth study of several compounds resulted in development of convenient parameters for reliable description of the structural and physical properties. It has been shown that the two parameters used to describe magnetic properties, the A-site ionic size and the size variance, are not sufficient for the cubic and slightly distorted crystal structures due to local strain effects arising from elongated bonds of transition-metal to oxygen. Complete structure-properties phase diagrams have been constructed and used to select unique compositions for demonstration of new materials capabilities.

2. Correlated Phenomena in Atomically Arranged Transition Metal Perovskites Primary Goal Indicator: Contributions Secondary Goal Indicators: Identifying new opportunities This work is notable because: The systematic exploration of the effects of composition, temperature, pressure, and oxygen content on thermodynamic stability and physical properties of transition metal perovskites have provided new tools for tailored production of desired materials. Application of design rules have demonstrated that novel compounds with unique properties can be predicted and produced, and provided new insights into many-body physics of transition metal oxides, electron correlations, and occurrence of novel ground states. The project has contributed to fundamental understanding and control of the organization of matter on the atomic scale for future application of perovskites in all-oxide multi-functional devices. Other Indicators (Is this work transformative or multidisciplinary?): This work involves multi-institutional and multidisciplinary research. Program Officer: L MADSEN NSF Award Numbers: 0302617 Award Title: Correlated Phenomena in Atomically Arranged Transition Metal Perovskites PI Name: Bogdan Dabrowski Institution Name: Northern Illinois University PE Code:

3. Correlated Phenomena in Atomically Arranged Transition Metal Perovskites Upper panel shows magnetic susceptibility of the ferromagnetic-insulator and superconducting superlattice exhibiting negative index of refraction. The inset shows schematically the composition of the sample. Lower panel shows resistivity (left) and superconducting penetration depth (right).