The Crystal Structure of FeAs.

Selte, Kari; Kjekshus, Arne; Sletten, Jorunn; Torbjörnsson, Lena; Werner, Per‐Erik; Junggren, Ulf; Lamm, Bo; Samuelsson, Benny

doi:10.3891/acta.chem.scand.23-2047

Cited by 33 publications

(29 citation statements)

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“…It is also different from the helical phase in FeAs [28,76,77], which displays a noncollinear spin density wave with the spin amplitude along the b-axis direction larger than that along the a direction. The magnetic iron moments refine to a uniform helical magnetic structure.…”

Section: The Magnetic Structure In X = 0141(5): Helical Magnetismentioning

confidence: 99%

Competing spin density wave, collinear, and helical magnetism inFe1+xTe

et al. 2017

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The Fe 1+x Te phase diagram consists of two distinct magnetic structures with collinear order present at low interstitial iron concentrations and a helical phase at large values of x with these phases separated by a Lifshitz point. We use unpolarized single-crystal diffraction to confirm the helical phase for large interstitial iron concentrations and polarized single-crystal diffraction to demonstrate the collinear order for the iron-deficient side of the Fe 1+x Te phase diagram. Polarized neutron inelastic scattering shows that the fluctuations associated with this collinear order are predominately transverse at low-energy transfers, consistent with a localized magnetic moment picture. We then apply neutron inelastic scattering and polarization analysis to investigate the dynamics and structure near the boundary between collinear and helical orders in the Fe 1+x Te phase diagram. We first show that the phase separating collinear and helical orders is characterized by a spin density wave with a single propagation wave vector of (∼0.45, 0, 0.5). We do not observe harmonics or the presence of a charge density wave. The magnetic fluctuations associated with this wave vector are different from the collinear phase, being strongly longitudinal in nature and correlated anisotropically in the (H,K) plane. The excitations preserve the C 4 symmetry of the lattice but display different widths in momentum along the two tetragonal directions at low-energy transfers. While the low-energy excitations and minimal magnetic phase diagram can be understood in terms of localized interactions, we suggest that the presence of the density wave phase implies the importance of electronic and orbital properties.

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Section: The Magnetic Structure In X = 0141(5): Helical Magnetismentioning

confidence: 99%

Competing spin density wave, collinear, and helical magnetism inFe1+xTe

et al. 2017

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“…In performing the first hightemperature study of MnP-type compounds, Heyding & Calvert (1957) discovered that CoAs transforms to an NiAs-type structure at about 1225 K, whereas FeAs approaches this structure as it nears melting [I343(20) K, Selte, Kjekshus & Andresen, 1972]. As part of a major investigation of MnP-type compounds, Selte & Kjekshus (1969) determined accurate structural parameters for FeAs from threedimensional single-crystal X-ray data, using the multiple-film technique with an integrated Weissenberg camera. Based on results from the Hamilton (1965) significance test, they concluded that Pna21 was the correct space group.…”

Section: Introductionmentioning

confidence: 99%

Room- and high-pressure crystal chemistry of CoAs and FeAs

Lyman¹,

Prewitt²

1984

Acta Crystallogr Sect B

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“…Each iron atom is coordinated by six arsenic atoms and within the Pnma group there are four different distances between iron and adjacent arsenic as two pairs of bonds lead to the same distances within the pair. However, a distortion leading to the lower symmetry Pna2 1 has been reported [15]. A distortion has probably more or less random character and leads to the iron displacements shown by arrows of Figure 5.…”

Section: Spin Spirals In Feasmentioning

confidence: 92%

Mössbauer studies of the peculiar magnetism in parent compounds of the iron-based superconductors

Jasek

Komędera

Błachowski

et al. 2014

Philosophical Magazine

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A review of the magnetism in the parent compounds of the iron-based superconductors is given based on the transmission Mössbauer spectroscopy of 57 Fe and 151 Eu. It was found that the 3d magnetism is of the itinerant character with varying admixture of the spin-polarized covalent bonds. For the '122' compounds a longitudinal spin density wave (SDW) develops. In the case of the EuFe 2 As 2 a divalent europium orders antiferromagnetically at much lower temperature as compared to the onset of SDW. These two magnetic systems remain almost uncoupled one to another. For the non-stoichiometric Fe 1+x Te parent of the '11' family one has a transversal SDW and magnetic order of the interstitial iron with relatively high and localized magnetic moments. These two systems are strongly coupled one to another. For the "grand parent" of the iron-based superconductors FeAs one observes two mutually orthogonal phase-related transversal SDW on the iron sites. There are two sets of such spin arrangements due to two crystallographic iron sites. The FeAs exhibits the highest covalency among compounds studied, but it has still a metallic character.

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The Crystal Structure of FeAs.

Cited by 33 publications

References 0 publications

Competing spin density wave, collinear, and helical magnetism inFe1+xTe

Competing spin density wave, collinear, and helical magnetism inFe1+xTe

Room- and high-pressure crystal chemistry of CoAs and FeAs

Mössbauer studies of the peculiar magnetism in parent compounds of the iron-based superconductors

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