Speed limit of the insulator–metal transition in magnetite

Abstract

As the oldest known magnetic material, magnetite (Fe3O4) has fascinated mankind for millennia. As the first oxide in which a relationship between electrical conductivity and fluctuating/localized electronic order was shown1, magnetite represents a model system for understanding correlated oxides in general. Nevertheless, the exact mechanism of the insulator–metal, or Verwey, transition has long remained inaccessible2,3,4,5,6,7,8. Recently, three-Fe-site lattice distortions called trimerons were identified as the characteristic building blocks of the low-temperature insulating electronically ordered phase9. Here we investigate the Verwey transition with pump–probe X-ray diffraction and optical reflectivity techniques, and show how trimerons become mobile across the insulator–metal transition. We find this to be a two-step process. After an initial 300 fs destruction of individual trimerons, phase separation occurs on a 1.5±0.2 ps timescale to yield residual insulating and metallic regions. This work establishes the speed limit for switching in future oxide electronics10.

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Figure 1: Experimental optical pump–X-ray probe set-up and response of the soft X-ray diffraction intensity from the monoclinic reflections of the low-temperature phase of Fe3O4 on optical pumping.
Figure 2: Differing femtosecond and picosecond responses for the decay of the trimeron-related X-ray diffraction intensity.
Figure 3: Fast trimeron lattice quench followed by a picosecond transformational process.
Figure 4: Summary of the workings of the Verwey transition in non-equilibrium pump–probe form.

References

  1. 1

    Verwey, E. J. W. Electronic conduction of magnetite (Fe3O4) and its transition point at low temperatures. Nature 144, 327–328 (1939).

    CAS  Article  Google Scholar 

  2. 2

    Nazarenko, E. et al. Resonant X-ray diffraction studies on the charge ordering in magnetite. Phys. Rev. Lett. 97, 056403 (2006).

    CAS  Article  Google Scholar 

  3. 3

    Lorenzo, J. E. et al. Charge and orbital correlations at and above the Verwey phase transition in magnetite. Phys. Rev. Lett. 101, 226401 (2008).

    CAS  Article  Google Scholar 

  4. 4

    Garcia, J. et al. Reexamination of the temperature dependences of resonant reflections in highly stoichiometric magnetite. Phys. Rev. Lett. 102, 176405 (2009).

    Article  Google Scholar 

  5. 5

    Piekarz, P., Parlinski, K. & Oles, A. M. Origin of the Verwey transition in magnetite: Group theory, electronic structure, and lattice dynamics study. Phys. Rev. B 76, 165124 (2007).

    Article  Google Scholar 

  6. 6

    Uzu, H. & Tanaka, A. Complex-orbital order in Fe3O4 and mechanism of the Verwey transition. J. Phys. Soc. Jpn 77, 074711 (2008).

    Article  Google Scholar 

  7. 7

    Garcia, J. & Subias, G. The Verwey transition—a new perspective. J. Phys. 16, R145 (2004).

    CAS  Google Scholar 

  8. 8

    Weng, S-C. et al. Direct observation of charge ordering in magnetite using resonant multiwave X-ray diffraction. Phys. Rev. Lett. 108, 146404 (2012).

    Article  Google Scholar 

  9. 9

    Senn, M. S., Wright, J. P. & Attfield, J. P. Charge order and three-site distortions in the Verwey structure of magnetite. Nature 481, 173–176 (2012).

    CAS  Article  Google Scholar 

  10. 10

    Yang, Z., Ko, C. & Ramanatha, S. Oxide electronics utilizing ultrafast metal-insulator transitions. Annu. Rev. Mater. Res. 41, 337–367 (2011).

    CAS  Article  Google Scholar 

  11. 11

    Fujii, Y., Shirane, G. & Yamada, Y. Study of the 123-K phase transition of magnetite by critical neutron scattering. Phys. Rev. B 11, 2036–2041 (1975).

    CAS  Article  Google Scholar 

  12. 12

    Shapiro, S. M., Iizumi, M. & Shirane, G. Neutron scattering study of the diffuse critical scattering associated with the Verwey transition in magnetite. Phys. Rev. B 14, 200–207 (1976).

    CAS  Article  Google Scholar 

  13. 13

    Weber, F. et al. Signature of checkerboard fluctuations in the phonon spectra of a possible polaronic metal La1.2Sr1.8Mn2O7 . Nature Mater. 8, 798–802 (2009).

    CAS  Article  Google Scholar 

  14. 14

    Imada, M., Fujimori, A. & Tokura, Y. Metal insulator transitions. Rev. Mod. Phys. 70, 1039–1263 (1998).

    CAS  Article  Google Scholar 

  15. 15

    Uehara, M., Mori, S., Chen, C. H. & Cheong, S-W. Percolative phase separation underlies colossal magnetoresistance in mixed valent mangatite. Nature 399, 560–563 (1999).

    CAS  Article  Google Scholar 

  16. 16

    Lai, K. et al. Mesoscopic percolating resistance network in a strained manganite thin film. Science 329, 190–193 (2010).

    CAS  Article  Google Scholar 

  17. 17

    Massee, F. et al. Bilayer manganites: Polarons on the verge of a metallic breakdown. Nature Phys. 7, 978–982 (2011).

    CAS  Article  Google Scholar 

  18. 18

    Pontius, N. et al. Time-resolved resonant soft x-ray diffraction with free-electron lasers: Femtosecond dynamics across the Verwey transition in magnetite. Appl. Phys. Lett. 98, 182504 (2011).

    Article  Google Scholar 

  19. 19

    Park, S. K., Ishikawa, T. & Tokura, Y. Charge-gap formation upon the Verwey transition in Fe3O4 . Phys. Rev. B 58, 3717–3720 (1998).

    CAS  Article  Google Scholar 

  20. 20

    Novelli, F. et al. Ultrafast optical spectroscopy of the lowest energy excitations in the Mott insulator compound YVO3: Evidence for Hubbard-type excitons. Phys. Rev. B 86, 165135 (2012).

    Article  Google Scholar 

  21. 21

    Emma, P. et al. First lasing and operation of an Ångstrom-wavelength free-electron laser. Nature Photon. 4, 641–647 (2010).

    CAS  Article  Google Scholar 

  22. 22

    Blasco, J., Garcia, J. & Subias, G. Structural transformation in magnetite below the Verwey transition. Phys. Rev. B 83, 104105 (2011).

    Article  Google Scholar 

  23. 23

    Huang, D. J. et al. Charge-orbital ordering and Verwey transition in magnetite measured by resonant soft X-ray scattering. Phys. Rev. Lett. 96, 096401 (2006).

    CAS  Article  Google Scholar 

  24. 24

    Schlappa, J. et al. Direct observation of t2g orbital ordering in magnetite. Phys. Rev. Lett. 100, 026406 (2008).

    CAS  Article  Google Scholar 

  25. 25

    Tanaka, A. et al. Symmetry of orbital order in Fe3O4 studied by Fe L2,3 resonant X-ray diffraction. Phys. Rev. Lett. 108, 227203 (2012).

    CAS  Article  Google Scholar 

  26. 26

    Lee, W. S. et al. Phase fluctuations and the absence of topological defects in a photo-excited charge-ordered nickelate. Nature Commun. 3, 838 (2012).

    CAS  Article  Google Scholar 

  27. 27

    Samuelson, E. J. & Steinsvoll, O. Low-energy phonons in magnetite. Phys. Status Solidi B 61, 615–620 (1974).

    Article  Google Scholar 

  28. 28

    Wu, Y. et al. High frequency scaled graphene transistors on diamond-like carbon. Nature 472, 74–78 (2011).

    CAS  Article  Google Scholar 

  29. 29

    Heimann, P. et al. Linac Coherent Light Source soft x-ray materials science instrument optical design and monochromator commissioning. Rev. Sci. Instrum. 82, 093104 (2011).

    Article  Google Scholar 

  30. 30

    Doering, D. et al. Development of a compact fast CCD camera and resonant soft X-ray scattering endstation for time-resolved pump–probe experiments. Rev. Sci. Instrum. 82, 073303 (2011).

    CAS  Article  Google Scholar 

Download references

Acknowledgements

Research at Stanford was supported through the Stanford Institute for Materials and Energy Sciences (SIMES) under contract DE-AC02-76SF00515 and the LCLS by the US Department of Energy, Office of Basic Energy Sciences. Portions of this research were carried out on the SXR Instrument at the LCLS, a division of SLAC National Accelerator Laboratory and an Office of Science user facility operated by Stanford University for the US Department of Energy. The SXR Instrument is funded by a consortium whose membership includes the LCLS, Stanford University through the Stanford Institute for Materials Energy Sciences (SIMES), Lawrence Berkeley National Laboratory (LBNL, contract number DE-AC02-05CH11231), University of Hamburg through the BMBF priority programme FSP 301, and the Center for Free Electron Laser Science (CFEL). The stay of M.S.G. at SLAC was made possible by support from FOM/NWO and the Helmholtz Virtual Institute Dynamic Pathways in Multidimensional Landscapes. The Cologne team was supported by the DFG through SFB 608 and by the BMBF (contract 05K10PK2). The University of Hamburg team was supported by the SFB 925 ‘Light induced dynamics and control of correlated quantum systems’. The Elettra-Sincrotrone Trieste and University of Trieste team was supported by European Union Seventh Framework Programme [FP7/2007–2013] under grant agreement number 280555 and by the Italian Ministry of University and Research under grant numbers: FIRB-RBAP045JF2 and FIRB-RBAP06AWK3. D.F., F.N., M.E. and F.P. thank F. Cilento and F. Randi for technical support.

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H.A.D., A.F., C.S-L. and W.W. conceived and planned the experiments. All authors except M.S.G. carried out the experiments. W.F.S., J.J.T., O.K., M.T. and P.K. provided excellent experimental guidance for using the SXR beamline and the LCLS optical laser system. W.S.L., Y.D.C., D.H.L., R.G.M., M.Y. and L.P. provided excellent support for the RSXS endstation. S.d.J. and R.K. performed the data analysis. D.F., F.N., M.E. and F.P. performed the time-resolved optical experiments and interpreted the optical data. S.d.J., R.K., M.S.G., C.S-L. and H.A.D. wrote the manuscript with help and input from all authors.

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Correspondence to C. Schüßler-Langeheine or H. A. Dürr.

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de Jong, S., Kukreja, R., Trabant, C. et al. Speed limit of the insulator–metal transition in magnetite. Nature Mater 12, 882–886 (2013). https://doi.org/10.1038/nmat3718

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