Effect of low-level titanium(IV) doping on the resistivity of magnetite near the Verwey transition

Ka̧kol, Z.; Sabol, J.; Stickler, J J; Honig, J.M.

doi:10.1103/physrevb.46.1975

Cited by 71 publications

(46 citation statements)

References 27 publications

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“…26 These features correspond to highly stoichiometric samples, Fe 3(1−δ) O 4 with δ ∼ = 0.000. 24,27,28 Synchrotron x-ray diffraction patterns were measured at the ID31 beamline at the ESRF (Grenoble, France). This is an insertion device with small-gap undulators and fine tuning of the magnets to permit both high-brilliance x rays and high collimation in the horizontal and vertical directions.…”

Section: Methodsmentioning

confidence: 99%

Structural transformation in magnetite below the Verwey transition

2011

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The magnetite structure was studied with synchrotron x-ray powder diffraction above and below the Verwey transition. A symmetry-mode analysis was performed to obtain the atomic displacements from the amplitudes of condensing modes. The main contributing modes that drive the structural phase transition at the Verwey temperature correspond to the irreducible representations 5 , X 1 , X 4 , W 1 , and W 2 . The W modes, neglected so far, must be taken into account so a reliable description of the low-temperature crystal structure can be obtained. This is refined in the nonpolar space group C2/c with ten nonequivalent octahedral irons. The condensation of the mentioned modes leads to a wide distribution of local environments around the octahedral iron atoms, whose valences range between 2.53 and 2.84. This finding rules out any bimodal charge disproportionation of the octahedral iron atoms, i.e., an Fe 2+ -like/Fe 3+ -like ordering.

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Section: Methodsmentioning

confidence: 99%

Structural transformation in magnetite below the Verwey transition

2011

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“…It is also not clear whether or not the exchange integral for Fe l p -Fe3 ś is different than the one for Fe3A+-Fe3B . A possible reason for such situation may follow from the fact that physical properties of magnetite are very sensitive to the oxygen stoichiometry [4], which, in turn is a derivative of sample preparation and its history. To illustrate this let us take the results obtained by means of the Mössbauer spectroscopy which is a very useful tool to study the issue.…”

Section: Introductionmentioning

confidence: 99%

Mössbauer-Effect Study of Calciomagnetites

et al. 1998

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Cax Fe3-x O4 samples, with x _ < 0.28, prepared from α-Fe 2 O 3 and CaO by the Bridgman method were investigated by means of 57 Fe Mossbauer spectroscopy. Room temperature spectra gave evidence that the samples were multiphase, the calciómagnetite being the dominant phase with a contribution of 73% to 99%, depending on the sample. Analysis of the subspectra associated with the calciomagnetite gave evidence that Ca-ions reside on the tetrahedral (A) sites and have not random distribution. Their presence on those sites causes a reduction of the hyperfine field at Fe nuclei occupying the octahedral positions (B) by 12.3(1.0) kOe per one Ca-ion and a decrease in the average hf field, (ΗB)/dx, at the rate of 29 kOe/mol% for x < 0.07 and of 387 kOe/mol% for larger x. In addition, a linear correlation between (ΗB) and the average isomer shift, (IB), was revealed to hold. It indicates that addition of Ca-ions into the magnetite causes a decrease in the spin-density and an increase in the charge-density at Fe nuclei occupying the B-sites.

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“…The strongest effect on Tv is caused by nonstoichiometry and Zn or Ti doping [1][2][3][4]. Despite the fact that all three kinds of defects introduce different perturbations to the system the properties of Fe3(ι-δ)O4 , Fe3-x ΤiO4 and Fe3 -x Ζn O 4 are very similar, which can be seen from the universal linear TV vs. 3δ = x dependence.…”

Section: Introductionmentioning

confidence: 58%

Heat Capacity and Elastic Constants of Fe_3-xZn_xO₄in the Vicinity of the Verwey Transition

et al. 2000

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The results of the heat capacity and elastic constant studies of Fe3-x Ζn x O 4 (x < 0.04) series are reported. Adiabatic heat capacity measurements, performed on single crystals, show the clear change of the transition character from first order for low Zn content (x < 0.012) to the higher order in 0.012 < x < 0.035 regime. The change of transition order is accompanied by the change in the heat capacity base lines below the Verwey transition temperature Tv. From the elastic constants measurements we found that cli, (Cl1 -c12) and c44 modes exhibit anomalies at Tv but only shear wave c44 show critical softening while approaching transition from high temperatures. This behavior can be linked to the results obtained by the heat capacity studies. These point to the important role of the lattice contribution to the mechanism of the Verwey transition.

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Effect of low-level titanium(IV) doping on the resistivity of magnetite near the Verwey transition

Cited by 71 publications

References 27 publications

Structural transformation in magnetite below the Verwey transition

Structural transformation in magnetite below the Verwey transition

Mössbauer-Effect Study of Calciomagnetites

Heat Capacity and Elastic Constants of Fe_3-xZn_xO₄in the Vicinity of the Verwey Transition

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Effect of low-level titanium(IV) doping on the resistivity of magnetite near the Verwey transition

Cited by 71 publications

References 27 publications

Structural transformation in magnetite below the Verwey transition

Structural transformation in magnetite below the Verwey transition

Mössbauer-Effect Study of Calciomagnetites

Heat Capacity and Elastic Constants of Fe3-xZnxO4in the Vicinity of the Verwey Transition

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Heat Capacity and Elastic Constants of Fe_3-xZn_xO₄in the Vicinity of the Verwey Transition