Prof. Alexander Gavriliuk [Russian Academy of Sciences, Russia]

Title: Magnetic, electronic and structural transitions at high pressures

Time: 10:00 - 11:00 AM, Thursday, November 12, 2015

Place: Conference Room 201, HPSTAR (Shanghai)

Host: Dr. Mao

Abstract:

The transition-metal oxides comprise a very broad class of compounds with diverse physical properties that are important in both fundamental science and practical applications. This class of materials includes high-temperature superconductors and giant magnetoresistance compounds, multiferroics, materials for spintronics and optoelectronics, various magnetic and magnetooptical crystals, and mixed oxides of iron and perovskite-like compounds of great importance in geophysics. The wide spectrum of different electron, magnetic, transport, and optical properties of these materials ensures a basis for novel kinds of applications in electronics.

The different scenarios and mechanisms of phase transformations at high pressures in strongly correlated transition metal oxides will be discussed. The complex approach to investigation is used, combining a wide veriety of experimental methods at high pressures and high and cryogenic temperatures: optical absorption/ reflection spectroscopy in IR, UV and visible regions, resistivity measurements, x-ray diffraction, conventional Mössbauer and synchrotron Mössbauer spectroscopy (NFS), x-ray emission spectroscopy (XES), Raman scattering spectroscopy, and more.

In this presentation, the results of recent experiments are summarized. I will review the studies of the effects of high pressure on the magnetic and crystal structures, on the electronic structure and spin states, and on transport and optical properties at the insulator-metal and semiconductor-insulator transitions in a number of simple and complex oxides of 3d metals. Theoretical approaches that are capable of explaining the effects of suppression of strong d-d electron correlations under high and ultrahigh pressures will be also discussed. In addition, I will outline main achievements and discoveries made while performing these studies.

Biography of the Speaker:

Prof. Alenxander Gavriliuk is from Institute of Crystallography, Russian Academy of Sciences, Moscow, Russia; Institute for Nuclear Research, Russian Academy of Sciences, Troitsk, Moscow, Russia; Geophysical Laboratory, Carnegie Institution of Washington, Washington DC, USA.