Temperature and Composition Dependence of the Cation Distribution in Synthetic ZnFeyAl2-yO4 (0 ≤ y ≤ 1) Spinels

Waerenborgh, J.C.; Figueiredo, M. Ondina; Cabral, J. M. P.; Pereira, L. C. J.

doi:10.1006/jssc.1994.1231

Cited by 111 publications

(69 citation statements)

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“…The spectra were fitted to Lorentzian lines using a nonlinear least-squares method. [29] Isomer shifts (Tables 1SS and 2SS in the Supporting Information) are given relative to metallic a-Fe at room temperature. …”

Section: Methodsmentioning

confidence: 99%

Multifunctional Magnetic Materials Obtained by Insertion of a Spin‐Crossover Fe^III Complex into Bimetallic Oxalate‐Based Ferromagnets

Clemente‐León

Coronado

López‐Jordà

et al. 2010

Chemistry A European J

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The syntheses, structures and magnetic properties of the compounds of formula [Fe(III)(sal(2)-trien)][Mn(II)Cr(III)(ox)(3)].CH(2)Cl(2) (1; H(2)sal(2)-trien=N,N'-disalicylidenetriethylenetetramine, ox=oxalate), [Fe(III)(sal(2)-trien)][Mn(II)Cr(III)(ox)(3)].CH(3)OH (2), [In(III)(sal(2)-trien)][Mn(II)Cr(III)(ox)(3)].0.25H(2)O.0.25CH(3)OH.0.25CH(3)CN (3), and [In(III)(sal(2)-trien)][Mn(II)Cr(III)(ox)(3)].CH(3)NO(2).0.5H(2)O (4) are reported. The structure of 1 presents a 2D honeycomb anionic layer formed by Mn(II) and Cr(III) ions linked through oxalate ligands and a cationic layer of [Fe(sal(2)-trien)](+) complexes intercalated between the 2D oxalate network. The structures of 2, 3, and 4 present a 3D achiral anionic network formed by Mn(II) and Cr(III) ions linked through oxalate ligands with [Fe(sal(2)-trien)](+) or [In(sal(2)-trien)](+) complexes and solvent molecules intercalated within the 3D oxalate network. The magnetic properties and Mössbauer spectroscopy of 1 and 2 indicate that these compounds undergo a long-range ferromagnetic ordering at around 5 K and a spin crossover of the intercalated [Fe(sal(2)-trien)](+) complexes above 130 K, which is complete in the case of 1. The magnetic properties of the compounds 3 and 4 confirm the ferromagnetic ordering of the bimetallic oxalate network.

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Section: Methodsmentioning

confidence: 99%

Multifunctional Magnetic Materials Obtained by Insertion of a Spin‐Crossover Fe^III Complex into Bimetallic Oxalate‐Based Ferromagnets

Clemente‐León

Coronado

López‐Jordà

et al. 2010

Chemistry A European J

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“…Mössbauer absorbers were prepared from a fraction of the same sample used for neutron diffraction, which was pressed together with lucite powder into perspex holders, in order to obtain homogeneous and isotropic absorbers containing about 5 mg/cm 2 of natural iron. Spectra were obtained at 295 and 5 K. Low-temperature measurements were performed using a liquid-nitrogen/liquid-helium flow cryostat, temperature stability G0.5 K. The spectra were fitted to Lorentzian lines using a non-linear least-squares computer method [10].…”

Section: Methodsmentioning

confidence: 99%

Structural and magnetic properties of UFe6Ga6

Gonçalves¹,

Waerenborgh²,

Sério³

et al. 2006

Intermetallics

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UFe 6 Ga 6 polycrystalline samples were prepared by arc-melting, and single crystals were grown by the Czochralski method. This compound crystallizes in the orthorhombic ScFe 6 Ga 6 -type structure (space group Immm, aZ5.0560(4), bZ8.5484(7) and cZ8.6914(7) Å ), an ordered variant of the ThMn 12 -type structure. A ferromagnetic-type transition at T C Z530(5) K is seen in the magnetization and A.C.-susceptibility measurements, and no other magnetic anomaly is observed down to 5 K. Single crystal magnetization measurements along the three different crystallographic axes indicated a as the easy direction, with a spontaneous magnetization M S Z12.3 m B /f.u. at 5 K. The analysis of the 57 Fe Mössbauer spectroscopy data indicated magnetic hyperfine fields, B hf , significantly lower on 4f sites than on 8k sites, in agreement with the trend already observed on UFe x Al 12Kx , where the average B hf were found to increase with the iron-iron interatomic distances. q

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“…(AEQ) for each spectrum were calculated as the weighted average of the n quadrupole splittings associated with each doublet of the fitted distribution. The Fe 3+ contribution to the spectra was fitted as a quadrupole doublet with hyperfine parameters typical of Fe 3 § in octahedral coordination in similar spinels: natural gahnites (Waerenborgh et al 1990) and ZnFeo.lAll.904 (Waerenborgh et al 1994).…”

Section: Fitting Strategy Of the M6ssbauer Spectramentioning

confidence: 99%

“…In order to contribute to a better understanding of the crystal chemistry of spinels within the system ZnO --A1203 --FeO--Fe203 structural investigations of the spinel solid solution series ZnFeyA12 _ yO 4 (0 < y ___ 2) and Zn~_xFexA1204 (0<x<l) were carried out (Waerenborgh 1992; Waerenborgh et al 1994). In this work we report the study on the synthetic Znx_xFexA1204 (0<x<l) spinels, using two independent methods, powder XRD and 57Fe M6ssbauer spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Powder XRD structure refinements and 57Fe M�ssbauer effect study of synthetic Zn1-xFexAl2O4 (0 < x ? 1) spinels annealed at different temperatures

Waerenborgh

Figueiredo²,

Cabral

et al. 1994

Phys Chem Minerals

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Abstract. Members of the solid solution seriesZnl_xF%A1204 (x = 0.2, 0.4, 0.6 and 1.0) with spinel structure were synthesized by direct solid-state reaction of the simple metal oxides and metallic iron in evacuated silica ampoules at 1175 ~ C. Two aliquots of the single-phase spinels obtained for each composition were annealed under vacuum at 1075 ~ C and 725 ~ C for 48 hours and then quenched in liquid nitrogen.The cation distributions of all the quenched samples were determined by X-ray powder diffraction, using the Rietveld method of structural refinement. The degree of inversion increases with iron content and for spinels with the same chemical composition with quenching temperature. The relative areas estimated for the contributions to the M6ssbauer spectra of tetrahedrally-and octahedrally-coordinated Fe 2+ suggest that most of Zn 2+ cations remain at the tetrahedral site, as expected from the relative cation site preferences.Failure to quench the equilibrium cation distributions, suggested by deviations between the observed composition dependence of the cation distribution and that expected from the thermodynamic model of O'Neill and Navrotsky (1983, 1984), may be explained by an enhancement of cation diffusion rates in the Znl_xF%A1204 (0 < x < 1) spinels caused by the presence of cation vacancies. Fe3+/vacancy defects are easily formed in these spinels due to partial oxidation of Fe z+ at high temperature.

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Temperature and Composition Dependence of the Cation Distribution in Synthetic ZnFeyAl2-yO4 (0 ≤ y ≤ 1) Spinels

Cited by 111 publications

References 0 publications

Multifunctional Magnetic Materials Obtained by Insertion of a Spin‐Crossover Fe^III Complex into Bimetallic Oxalate‐Based Ferromagnets

Multifunctional Magnetic Materials Obtained by Insertion of a Spin‐Crossover Fe^III Complex into Bimetallic Oxalate‐Based Ferromagnets

Structural and magnetic properties of UFe6Ga6

Powder XRD structure refinements and 57Fe M�ssbauer effect study of synthetic Zn1-xFexAl2O4 (0 < x ? 1) spinels annealed at different temperatures

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Temperature and Composition Dependence of the Cation Distribution in Synthetic ZnFeyAl2-yO4 (0 ≤ y ≤ 1) Spinels

Cited by 111 publications

References 0 publications

Multifunctional Magnetic Materials Obtained by Insertion of a Spin‐Crossover FeIII Complex into Bimetallic Oxalate‐Based Ferromagnets

Multifunctional Magnetic Materials Obtained by Insertion of a Spin‐Crossover FeIII Complex into Bimetallic Oxalate‐Based Ferromagnets

Structural and magnetic properties of UFe6Ga6

Powder XRD structure refinements and 57Fe M�ssbauer effect study of synthetic Zn1-xFexAl2O4 (0 < x ? 1) spinels annealed at different temperatures

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Product

Resources

About

Multifunctional Magnetic Materials Obtained by Insertion of a Spin‐Crossover Fe^III Complex into Bimetallic Oxalate‐Based Ferromagnets

Multifunctional Magnetic Materials Obtained by Insertion of a Spin‐Crossover Fe^III Complex into Bimetallic Oxalate‐Based Ferromagnets