Abstract
Charge ordering creates a spontaneous array of differently charged ions and is associated with electronic phenomena such as superconductivity, colossal magnetoresistances (CMR), and multiferroicity. Charge orders are usually suppressed by chemical doping and site selective doping of a charge ordered array has not previously been demonstrated. Here we show that selective oxidation of one out of eight distinct Fe2+ sites occurs within the complex Fe2+/Fe3+ ordered structure of 2%-doped magnetite (Fe3O4), while the rest of the charge and orbitally ordered network remains intact. This ‘charge order within a charge order’ is attributed to the relative instability of the trimeron distortion surrounding the selected site. Our discovery suggests that similar complex charge ordered arrays could be used to provide surface sites for selective redox reactions, or for storing information by doping specific sites.
Highlights
Charge ordering creates a spontaneous array of differently charged ions and is associated with electronic phenomena such as superconductivity, colossal magnetoresistances (CMR), and multiferroicity
Charge ordering is associated with notable electronic phenomena such as superconductivity in copper[1] and bismuth[2] oxides, CMR in manganese oxide perovskites[3] and multiferroicity in iron oxides[4]
Charge orders are usually suppressed by doping in a few cases such as CMR manganese oxides, the entire array rearranges into a new periodicity[5]
Summary
Charge ordering creates a spontaneous array of differently charged ions and is associated with electronic phenomena such as superconductivity, colossal magnetoresistances (CMR), and multiferroicity. Charge orders are usually suppressed by chemical doping and site selective doping of a charge ordered array has not previously been demonstrated. We show that selective oxidation of one out of eight distinct Fe2+ sites occurs within the complex Fe2+/Fe3+ ordered structure of 2%-doped magnetite (Fe3O4), while the rest of the charge and orbitally ordered network remains intact. This ‘charge order within a charge order’ is attributed to the relative instability of the trimeron distortion surrounding the selected site. Inequivalent cations of the same charge should, in principle, have slightly different redox potentials, but site selective doping of a charge ordered array has not previously been demonstrated. We show that highly selective doping is observed in a lightly oxidised magnetite microcrystal, where one of eight distinct Fe2+
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
