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.
Speed limit of the insulator–metal transition in magnetite / S., de Jong; R., Kukreja; C., Trabant; N., Pontius; C. F., Chang; T., Kachel; M., Beye; F., Sorgenfrei; C. H., Back; B., Bräuer; W. F., Schlotter; J. J., Turner; O., Krupin; M., Doehler; D., Zhu; M. A., Hossain; A. O., Scherz; Fausti, Daniele; F., Novelli; Esposito, Martina; W. S., Lee; Y. D., Chuang; D. H., Lu; R. G., Moore; M., Yi; M., Trigo; P., Kirchmann; L., Pathey; M. S., Golden; M., Buchholz; P., Metcalf; Parmigiani, Fulvio; W., Wurth; A., Föhlisch; C., Schüßler Langeheine; H. A., Dürr. - In: NATURE MATERIALS. - ISSN 1476-1122. - ELETTRONICO. - (2013), pp. 1-5. [10.1038/NMAT3718]
Speed limit of the insulator–metal transition in magnetite
FAUSTI, DANIELE;ESPOSITO, MARTINA;PARMIGIANI, FULVIO;
2013-01-01
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.Pubblicazioni consigliate
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