Effect of low Zn doping on the Verwey transition in magnetite single crystals: Mössbauer spectroscopy and x-ray diffraction

Chlan, V.; Żukrowski, J.; Bosak, A.; Ka̧kol, Z.; Kozłowski, A.; Tarnawski, Z.; Řezníček, R.; Štěpánková, H.; Novák, P.; Bialo, I.; Honig, J.M.

doi:10.1103/physrevb.98.125138

Cited by 20 publications

(21 citation statements)

References 33 publications

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“…It was originally thought that second-order samples did not show a structural transition at T V , but a subsequent study reported that a distortion of the cubic cell is present in the second-order regime, modelled with a rhombohedral R 3m cell 18 . A recent Mössbauer and room temperature diffraction study suggested a change of lattice symmetry for Fe 3-z Zn z O 4 between firstand second-order regimes 19 Fig. 1 Characterisation of magnetite samples.…”

Section: Resultsmentioning

confidence: 99%

Site-selective doping of ordered charge states in magnetite

et al. 2020

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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 Fe 2+ sites occurs within the complex Fe 2+ /Fe 3+ ordered structure of 2%-doped magnetite (Fe 3 O 4), 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.

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Section: Resultsmentioning

confidence: 99%

Site-selective doping of ordered charge states in magnetite

et al. 2020

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“…Мёссбауэровские спектры макрокристаллов магнетита при комнатной температуре, на которых наблюдается два секстиплета, соответствующие катионам Fe в кристаллической решетки магнетита, хорошо известны в литературе (см., например, [31,54,55] [31,64], что связано с меньшими размерами компонентов исследуемых НК. Величины изомерных сдвигов (δ) и H e f f согласуются с данными для наночастиц магнетита размерами от 10 до 20 nm (см., например, [57,64]).…”

Section: анализ мёссбауэровских спектров нк Fe 3 O 4 /γ-Fe 2 O 3 комнunclassified

Мёссбауэровские исследования состава и магнитной структуры нанокомпозитов Fe-=SUB=-3-=/SUB=-O-=SUB=-4-=/SUB=-/γFe-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=- типа ядро--оболочка при температура 300 и 80 K (Часть I)

Kamzin¹,

Obaidat

Валлиулин³

et al. 2020

Физика Твердого Тела

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The results of Mössbauer studies of the magnetic structure and composition of Fe3O4 / γ-Fe2O3 nanoparticles at temperatures of 300 and 80 K are presented. It was found that particles Fe3O4 /γ-Fe2O3 is a core / shell nanocomposite (NC) in which magnetite (Fe3O4) is a coated by shell of maghemite (γ-Fe2O3). It was shown that the thickness of the maghemite (γ-Fe2O3) shell depends on the synthesis technology. It was found that, in the Fe3O4 /γ-Fe2O3 NC, on the surface of the maghemite (γ-Fe2O3) shell, a layer whose magnetic structure differs from the structure of the inner part of the shell (γ-Fe2O3). An intermediate layer is formed between the core and the shell in a spin-glass state. The obtained data on the structure of core / shell nanocomposites open up prospects for explaining the properties of such particles, which are of great interest for applications in various fields, including biomedicine.

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“…Differences in parameters defining the sextets [hyperfine magnetic fields B eff , electric field gradient affecting quadrupole splitting (QS), and isomer shift (IS)] within these groups are too subtle to be revealed separately and the differences among these groups are relatively high. Consequently, only four groups were proposed to be important for the analysis, and this procedure was successfully applied in the interpretation of Mössbauer spectra in stoichiometric [30] and Zn-doped magnetite [11]. The same procedure will be used here, although it is strictly valid only in a zero external magnetic field [29], as discussed below.…”

Section: A Crystal Lattice Below T Vmentioning

confidence: 99%

“…[30], was successfully used in Ref. [11], and is used here may not be applicable when the magnetization is rotated to some direction other than along c M . Consequently, we might expect that the MS spectrum in the magnetic field (especially as large as 7 T) after ZFC will be substantially different from the relevant spectra after FC and AS.…”

Section: High-field Spectramentioning

confidence: 99%

“…The cubic phase may be regarded as a dynamic collection of less symmetric atomic/electronic arrangements that average to a mean cubic state. The behavior of those arrangements may be linked to the still unresolved problem of the Verwey transition of first and second order [11,12]. With such a variety of phenomena and mutually cooperating subsystems, it is interesting to see to what extent those subsystems can be manipulated by an external trigger, such as an electric field [13], light [14], or a magnetic field [15,16].…”

Section: Introductionmentioning

confidence: 99%

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Magnetic field induced structural changes in magnetite observed by resonant x-ray diffraction and Mössbauer spectroscopy

Kołodziej¹,

Bialo

Tabiś

et al. 2020

Phys. Rev. B

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When a magnetic field is applied to a single crystal of magnetite at 124 K > T > 50 K, the monoclinic c M axis, which is the easy magnetization axis, switches to one of the 100 cubic directions, nearest to the direction of the magnetic field, and the phenomenon known as an axis switching (AS) occurs. A global symmetry probe, resonant x-ray scattering, and a local probe, Mössbauer spectroscopy, are used to better understand the mechanism of axis switching. The behavior of three subsystems ordered below the Verwey transition temperature T V , i.e., lattice distortion, an orbital, and charge orderings, was observed via resonant x-ray scattering as a function of an external magnetic field. This was preceded by calculation of selected peak intensities using the FDMNES code. The Mössbauer spectroscopy studies confirmed that the magnetic field triggers electronic rearrangements and atomic displacements. The structure observed after the process of axis switching is very similar to the one obtained after cooling below T V with the magnetic field applied along one of the initial 100 cubic directions and distinct from the cooling in the absence of a magnetic field. From all the experimental observations of the phenomenon done so far, it is clear that AS starts from the fluctuations between octahedral iron orbitals that ultimately lead to the Verwey transition, but also to the higher-temperature trimeron dynamics. Therefore, further observation of the axis switching may be a key point to the understanding of a majority of strongly correlated electronic behavior in magnetite as well as in other transition metal oxides.

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Effect of low Zn doping on the Verwey transition in magnetite single crystals: Mössbauer spectroscopy and x-ray diffraction

Cited by 20 publications

References 33 publications

Site-selective doping of ordered charge states in magnetite

Site-selective doping of ordered charge states in magnetite

Magnetic field induced structural changes in magnetite observed by resonant x-ray diffraction and Mössbauer spectroscopy

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