Structure and magnetism in synthetic pyrrhotite<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>Fe</mml:mtext></mml:mrow><mml:mn>7</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">S</mml:mi><mml:mn>8</mml:mn></mml:msub></mml:mrow></mml:math>: A powder neutron-diffraction study

Powell, Anthony V.; Vaqueiro, Paz; Knight, Kevin S.; Chapon, L. C.; Sánchez, R.D.

doi:10.1103/physrevb.70.014415

Cited by 127 publications

(146 citation statements)

References 25 publications

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“…The sharp change in the magnetization at the temperature T C z 205 K is indicative of the magnetic phase transition from a magnetically ordered state to the paramagnetic state with increasing temperature. This Curie temperature is substantially lower than that observed for Fe 7 S 8 [3], which means that the substitution of Ti for Fe atoms reduces the exchange interactions. …”

Section: Methodsmentioning

confidence: 49%

“…It is worth to mention that according to neutron diffraction measurements iron atoms in Fe 7 S 8 have a lower value of the ordered magnetic moment (ca. 74%) than the expected spin-only moment [3]. A significant decrease in the ordered moments (to w50%) from the spin-only value was also observed in the Ni x Cr 3Àx S 4 system with the NiAs structure type [21].…”

Section: Discussionmentioning

confidence: 60%

“…4, we estimated the saturation magnetization M s ¼ 47 emu g À1 at T ¼ 2 K by using the law of approach to saturation [16]. This value corresponds to 5.25m B per formula unit (m FU ) which is substantially higher than m FU ¼ (2.03e2.53)m B reported for Fe 7 S 8 in the literature [3,17]. The enhanced value of the saturation magnetization in our Fe 4 Ti 3 S 8 compound in comparison with non-substituted Fe 7 S 8 may be ascribed to the non-statistical distribution of substituents (Ti atoms) over the crystal lattice.…”

Section: Resultsmentioning

confidence: 79%

“…The vacancies are ordered in some iron layers, in a way that there is a layer of full Fe sites followed by a layer of Fe sites with vacancies. According to a neutron diffraction study [3], the magnetic moments of iron atoms in Fe 7 X 8 are coupled ferromagnetically inside each iron layer, but coupled antiferromagnetically between adjacent layers. The presence of vacancies in some iron layers leads to incomplete cancellation of magnetic moments, resulting in the appearance of ferrimagnetism in Fe 7 S 8 and Fe 7 Se 8 systems below Curie temperatures of about 590 K [1,4] and 480 K [5], respectively.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Pseudobinary Fe4Ti3S8 compound with a NiAs-type structure: Effect of Ti for Fe substitution

Ibrahim¹,

Selezneva²,

Губкин³

et al. 2013

Solid State Sciences

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a b s t r a c tThe transition metal sulfide Fe 4 Ti 3 S 8 with 7:8 composition has been synthesized and studied by using X-ray diffraction, magnetization and electrical resistivity measurements. This compound exhibits a monoclinic crystal lattice (space group I12/m1). The substitution of Ti for Fe in Fe 7 S 8 is found to result in a lowering of the Curie temperature (T C z 205 K), in a larger value of the coercive field (H c w 9 kOe at low temperatures) and in a substantial growth of the resultant magnetic moment per formula unit (m FU ) in comparison with Fe 7 S 8 . An enhanced value of m FU is attributed to the preferential substitution of Ti in alternating cation layers. From the paramagnetic susceptibility measured within temperature interval (250e350) K, a reduced value of the effective moment per iron (m Fe w 2.4m B ) was determined. The electrical resistivity of Fe 4 Ti 3 S 8 shows a non-metallic behavior and is affected by magnetic ordering.

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Section: Methodsmentioning

confidence: 49%

Section: Discussionmentioning

confidence: 60%

Section: Resultsmentioning

confidence: 79%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Pseudobinary Fe4Ti3S8 compound with a NiAs-type structure: Effect of Ti for Fe substitution

Ibrahim¹,

Selezneva²,

Губкин³

et al. 2013

Solid State Sciences

View full text Add to dashboard Cite

show abstract

“…Voisey's Bay; Naldrett et al, 2000). The more frequently occurring magnetic pyrrhotite is known as 4C pyrrhotite, has an ideal composition Fe 7 S 8 and monoclinic crystallography (Powell et al, 2004). Nonmagnetic pyrrhotite is formally described as NC pyrrhotite where N is an integer between 5 and 11 (Morimoto et al 1970).…”

Section: Introductionmentioning

confidence: 99%

The flotation of magnetic and non-magnetic pyrrhotite from selected nickel ore deposits

Becker

Villiers

Bradshaw

2010

Minerals Engineering

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a b s t r a c tThe non-stoichiometric sulfide mineral pyrrhotite (Fe (1Àx) S), common to many nickel ore deposits, occurs in different crystallographic forms and compositions. A series of pyrrhotite samples derived from Canada, South Africa and Botswana whose mineralogy is well characterised, were selected here in order to develop the relationship between mineralogy and flotation performance. Using both oxygen uptake and microflotation tests, the behaviour of the different pyrrhotite types was compared in terms of the effect of pH and collector addition. Non-magnetic pyrrhotite was less reactive in terms of its oxygen uptake and showed the best collectorless flotation recovery. Magnetic pyrrhotite was more reactive and showed poor collectorless flotation performance that could be improved with the addition of xanthate collector, but only if it was not already passivated. These differences are interpreted to be a result of pyrrhotite mineralogy. This has implications that may aid the manipulation of pyrrhotite flotation performance in processing operations.

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Unusual Magnetic Properties of Sedimentary Pyrrhotite in Methane Seepage Sediments: Comparison With Metamorphic Pyrrhotite and Sedimentary Greigite

Horng

2018

JGR Solid Earth

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Interpretation of the paleomagnetic and environmental signals carried by magnetic iron sulfide minerals depends on the ability to diagnose their magnetic properties and to recognize their origin. Greigite (Fe3S4) and hexagonal pyrrhotite (with variable composition between Fe9S10 and Fe11S12) often form authigenically in sulfidic and methanic sedimentary environments, whereas monoclinic pyrrhotite (Fe7S8) occurs widely in igneous and metamorphic rocks so that erosion of such rocks can give rise to deposition of detrital pyrrhotite in sediments. In this study, low‐ and high‐field, and low‐, room temperature, and high‐temperature magnetization data are presented to demonstrate that these magnetic iron sulfide minerals have contrasting magnetic properties that enable their identification, particularly when assisted by mineralogical characterizations. The results presented here should have wide applicability in sedimentary magnetic studies.

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Structure and magnetism in synthetic pyrrhotiteFe7S8: A powder neutron-diffraction study

Cited by 127 publications

References 25 publications

Pseudobinary Fe4Ti3S8 compound with a NiAs-type structure: Effect of Ti for Fe substitution

Pseudobinary Fe4Ti3S8 compound with a NiAs-type structure: Effect of Ti for Fe substitution

The flotation of magnetic and non-magnetic pyrrhotite from selected nickel ore deposits

Unusual Magnetic Properties of Sedimentary Pyrrhotite in Methane Seepage Sediments: Comparison With Metamorphic Pyrrhotite and Sedimentary Greigite

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