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Attenborough, M.; Hall, I.; Nikolov, O.; Brown, S.R.

doi:10.1023/a:1012651921896

Cited by 5 publications

(2 citation statements)

References 10 publications

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“…The symmetry of the magnetic structure is consistent with either a first-order transition or two successive transitions, the latter being consistent with the presence of two anomalies observed in the low temperature region of the heat capacity (ca 6.9 and 7.2 K). This scenario is also in agreement with experiments conducted by Mösssbauer spectroscopy [27] and muon spin relaxation, [28] both pointing to the occurrence of two distinct magnetic structures. This sequence of transitions suggests that two order parameters directed respectively along the a-or c-crystallographic axis (and belonging to Γ 1 and Γ 2 ), condense in turn at T FE and T N .…”

Section: Magnetic Structuresupporting

confidence: 91%

Magnetically-induced ferroelectricity in the (ND4)2[FeCl5(D2O)] molecular compound

Rodríguez-Velamazán

Fabelo

Millán

et al. 2015

Sci Rep

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The number of magnetoelectric multiferroic materials reported to date is scarce, as magnetic structures that break inversion symmetry and induce an improper ferroelectric polarization typically arise through subtle competition between different magnetic interactions. The (NH4)2[FeCl5(H2O)] compound is a rare case where such improper ferroelectricity has been observed in a molecular material. We have used single crystal and powder neutron diffraction to obtain detailed solutions for the crystal and magnetic structures of (NH4)2[FeCl5(H2O)], from which we determined the mechanism of multiferroicity. From the crystal structure analysis, we observed an order-disorder phase transition related to the ordering of the ammonium counterion. We have determined the magnetic structure below TN, at 2 K and zero magnetic field, which corresponds to a cycloidal spin arrangement with magnetic moments contained in the ac-plane, propagating parallel to the c-axis. The observed ferroelectricity can be explained, from the obtained magnetic structure, via the inverse Dzyaloshinskii-Moriya mechanism.

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Section: Magnetic Structuresupporting

confidence: 91%

Magnetically-induced ferroelectricity in the (ND4)2[FeCl5(D2O)] molecular compound

Rodríguez-Velamazán

Fabelo

Millán

et al. 2015

Sci Rep

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“…The crystals of (NH 4 ) 2 [FeCl 5 (H 2 O)] have been usually prepared by slow evaporation of aqueous solutions containing a (1-2):1 molar mix of NH 4 Cl and FeCl 3 ·6H 2 O (Sharma 1974, Figgis 1978, McElearney 1978, Partiti 1985. This compound was also obtained from hydrochloric acid solutions (Attenborough 1997). This paper is a continuation of our previously reported studies on spectral and structural properties of iron complexes with derivatives of pyridine (Ondrejkovičová et al , 2009Štefániková et al 2008).…”

Section: Introductionmentioning

confidence: 99%

A new pathway of preparation and refined structure of (NH4)2[FeCl5(H2O)]

Lacková¹,

Ondrejkovičová²,

Koman³

2013

Acta Chimica Slovaca

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The title compound, (NH 4 ) 2 [FeCl 5 H 2 O] has been prepared by reaction between iron(III) chloride and ammonium chloride which was formed by hydrolysis of isonicotinamide or thionicotinamide in ethanol. The characterization was based on elemental analysis and infrared spectra. The crystal structure of the title compound has been refi ned by single crystal X-ray diffraction method at 293 K. Crystals are orthorhombic, Pnma, with unit cell parameters: a = 13.760(1) Å, b = 9.960(1) Å, c = 7.060(1) Å, Z = 4 and R = 3.5 %. The iron(III) atom in [FeCl 5 2-ion is approximately octahedrally coordinated by fi ve Cl atoms and one O atom of H 2 O molecule. This distortion is caused by the extensively hydrogen-bonded lattice. Structural parameters and IR spectra of similar compounds are compared and discussed.

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