COLLABORATION IN BASIC SCIENCE AND ENGINEERING (COBASE)

In February 2001, Raymond Jeanloz hosted Alexander Gavriliuk of the Institute for High-Pressure Physics in Troitsk, Russia. The goal of Gavriliuk’s three-week visit to Berkeley was to lay the groundwork for research on Mott insulators (nickel monoxide and other metal monoxides) and charge-transfer insulators (rare-earth orthoferrites) at high pressures. Studies of these materials should help to advance our understanding of the physics of strongly correlated electronic systems, high-temperature superconductivity, and mechanisms of magnetic ordering in relations to electronic structure. In addition, they are of fundamental importance in revealing the nature of bonding in geophysically relevant systems, including analogs for deep-Earth phases, giving the work broad significance for the Earth and planetary sciences.

During Gavriliuk’s visit, he and Jeanloz carried out preparatory work towards preparing a draft proposal on the phase diagram and bonding states of Fe3O4 at lower-mantle conditions. They reviewed the relevant literature and then completed and analyzed some preliminary measurements using various spectroscopic methods. Synchrotron-based optical-absorption measurements were made at high pressures, thus indicating that a key element of the proposed research can be completed successfully. The proposal is now being completed for submission to the appropriate funders.