Orbital domain dynamics in Magnetite below the Verwey transition

ORAL

Abstract

Mesoscale phenomena play an important role in the dynamics of phase transitions in correlated systems. In order to fully understand and tailor their functionalities detailed access to the nanoscale regime, correlation length scales and temporal evolution of the order parameter is required. In this study, we utilized X-ray photon correlation spectroscopy (XPCS) to investigate the orbital domain dynamics of the insulating phase undergoing the insulator-to-metal transition in magnetite (Tv=123 K). XPCS provides a unique way to characterize disorder (domains, phase separation etc.) and their correlations by allowing us to capture high resolution coherent speckle patterns. By tuning to the Fe L3-edge, we studied the evolution of the orbitally ordered superlattice peak present in the low temperature insulating phase and forbidden in the metallic phase. We observed two distinct regimes below the Verwey transition. In the first regime at lower temperatures, magnetite follows an Arrhenius behavior and the characteristic timescale for orbital fluctuations decreases as the temperature increases. In the second regime near Tv, magnetite phase separates into metallic and insulating domains, and the kinetics of phase transition is dictated by metallic-insulating interfacial boundary conditions.

–

Presenters

  • Roopali Kukreja

    Univ of California - Davis, University of California Davis

Authors

  • Roopali Kukreja

    Univ of California - Davis, University of California Davis

  • Nelson Hua

    University of California San Diego, University of California, San Diego

  • Josh Ruby

    University of California, San Diego

  • Andi Barbour

    National Synchrotron Light Source II, Brookhaven National Laboratory, Brookhaven National Laboratory

  • Wen Hu

    Brookhaven National Laboratory, National Synchrotron Light Source II, Brookhaven National Laboratory

  • Claudio Mazzoli

    PS, BNL, National Synchrotron Light Source II, Brookhaven National Laboratory, Brookhaven National Lab, Brookhaven National Laboratory

  • Stuart Wilkins

    National Synchrotron Light Source II, Brookhaven National Laboratory, Brookhaven National Lab, Brookhaven National Laboratory

  • Eric Fullerton

    Center for Memory Research, Univ of California - San Diego, University of California San Diego, University of California, San Diego, Center for Memory and Recording Research, University of California, San Diego, Center for Memory Recording Research, University of California San Diego, Center for Memory and Recording Research, University of California San Diego, Center for Memory and Recording Research, Univ of California - San Diego

  • Oleg Shpyrko

    Department of Physics, Univ of California - San Diego, University of California, San Diego, University of California San Diego