Structural, electronic and magnetic properties of oxides at high pressures and temperatures: new polymorphs, new insights and new possible applications

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In this project we will investigate structural, electronic, optical, and magnetic properties of new oxide polymorphs that are stabilized in conditions of high pressures and high temperatures (HP-HT). The overall scientific goals of the present project are as follows:(i) A search for new high-pressure high-temperature (HP-HT) polymorphs in oxides. These studies will include HP-HT synthesis in large-volume multi-anvil cells in ranges up to 25 GPa and up to 2500 K, as well as in-situ high-pressure studies in diamond anvil cells with a possibility of laser heating, in ranges up to 100 GPa and up to 3000 K.(ii) Detailed investigations of physical properties of new polymorphs in both ex-situ studies on samples recovered after HP-HT treatment and in in-situ high-pressure studies. We plan to use several experiment techniques, e.g., powder and single-crystal X-ray diffraction, micro-Raman spectroscopy, Infrared, near Infrared and visual absorption spectroscopy, micro-probe, SEM and TEM analyses, electron diffraction, neutron diffraction, nanoindentation, measurements of electrical resistivity, thermoelectric power, Hall effect, magnetoresistance, magnetic susceptibility, electrical polarization, and some others.The proposed work would have the following major implications:(i) New unusual materials prepared at HP-HT conditions often reveal new scientific puzzles that may play an important role in advancing the science. In this project we will investigate several such cases found in new iron oxide Fe4O5, perovskite-type Mn2O3, and in other systems. (ii) We prepare and investigate several new oxides that may be promising for future industrial applications, e.g. new hard direct-band gap semiconductors that can be widely used in semiconductor industry, new multiferroics for possible applications in magnetic and piezo- elements, new smart materials for a wide range of applications.Thus, this project should make a significant contribution to understanding of physics of oxide systems. Some findings can also have implications for industrial applications.