Dataset associated with 'Vogel-Fulcher-Tammann Freezing of a Thermally Fluctuating Arti cial Spin Ice Probed by X-ray Photon Correlation Spectroscopy'

  1. Morley, Sophie Ann 1
  2. Alba Venero, Diego 2
  3. Porro, Jose Maria 2
  4. Riley, Susan T. 1
  5. Stein, Aaron 3
  6. Steadman, Paul 4
  7. Stamps, Robert 5
  8. Langridge, Sean 2
  9. Marrows, Christopher 1
  1. 1 University of Leeds
    info

    University of Leeds

    Leeds, Reino Unido

    ROR https://ror.org/024mrxd33

  2. 2 ISIS Neutron and Muon Source
  3. 3 Brookhaven National Laboratory
    info

    Brookhaven National Laboratory

    Ridge, Estados Unidos

    ROR https://ror.org/02ex6cf31

  4. 4 Diamond Light Source
  5. 5 University of Glasgow
    info

    University of Glasgow

    Glasgow, Reino Unido

    ROR https://ror.org/00vtgdb53

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Editor: University of Leeds

Any de publicació: 2017

Tipus: Dataset

CC BY 4.0

DOI: 10.5518/59 lock_openAccés obert editor

Resum

We report on the crossover from the thermal to athermal regime of an arti cial spin ice formed from a square array of magnetic islands whose lateral size, 30 nm 70 nm, is small enough that they are superparamagnetic at room temperature. We used resonant magnetic soft x-ray photon correlation spectroscopy (XPCS) as a method to observe the time-time correlations of the uctuating magnetic con gurations of spin ice during cooling, which are found to slow abruptly as a freezing temperature T0 = 178 5 K is approached. This slowing is well-described by a Vogel-Fulcher-Tammann law, implying that the frozen state is glassy, with the freezing temperature being commensurate with the strength of magnetostatic interaction energies in the array. The activation temperature, TA = 40 10 K, is much less than that expected from a Stoner-Wohlfarth coherent rotation model. Zero- eld-cooled/ eld-cooled magnetometry reveals a freeing up of uctuations of states within islands above this temperature, caused by variation in the local anisotropy axes at the oxidised edges. This Vogel-Fulcher-Tammann behavior implies that the system enters a glassy state on freezing, which is unexpected for a system with a well-defined ground state..