Electronic and magnetic properties of the pyrite-structure compound NiS<sub>2</sub>: influence of vacancies and copper impurities

Krill, G.; Lapierre, M.F.; Robert, C.; Gautier, François; Czjzek, G.; Fink, J.; Schmidt, Helmut

doi:10.1088/0022-3719/9/5/016

Cited by 72 publications

(60 citation statements)

References 27 publications

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“…The data set for NiS2 was collected at the reduced accelerating voltage of 45 kV in order to avoid contributions of a/2 radiation which would mainly contaminate the intensities of reflections with mixed indices; this would lead to biased results and in particular to a biased site-occupancy parameter for S. This aspect is more important for NiS2 since, in contrast to COS2, a range of nonstoichiometric compositions is known. The lattice parameter is a measure of the nickel vacancy concentration (Krill et al, 1976) and special care was therefore taken to determine its value precisely. For this purpose, the 20 angles of 40 reflections in the range 44 < 20 < 82 ° were measured on both sides of the primary beam.…”

Section: Methodsmentioning

confidence: 99%

“…The least-squares refinement using the resulting 20 values led to a lattice parameter of 5.6852 ~, (Table 1) which corresponds to the composition NISI.97. According to Krill et al (1976), NiSx in the range 1-91 ___ x---2.1 has a nearly constant S-vacancy concentration of about 4% , the variation in x being due to Ni vacancies. The Ni-vacancy concentration of the particular crystal used in our experiments is therefore about 2.7%.…”

Section: Methodsmentioning

confidence: 99%

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Charge densities in CoS₂ and NiS₂ (pyrite structure)

Nowack¹,

Schwarzenbach²,

Hahn³

1991

Acta Crystallogr Sect B

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The electron-density distributions in the pyrite-type structures of CoS2 and NiS2 have been determined from high-resolution single-crystal diffraction data [Ag Ka radiation; resolution and temperature (sin0/A)max = 1"49 /~-I at 295 K for COS2, 1.63 ~-1 at 135 K for NiS2]. The charge densities were refined using a multipolar deformation model [R(IFI) = 0.0119 and 0.0136, respectively]. The X-ray diffraction data of FeS2 [Stevens, DeLucia & Coppens (1980). lnorg. Chem. 19, 813-820; Ag Ka radiation, (sin0/a)m.x = 1.46 A-i, room temperature] were refined using the same deformation model and program in order to facilitate comparison of the results [R(IFI) = 0.0176]. The main features of the resulting deformation maps agree well for all three structures. They consist of important maxima in the immediate vicinity of the metal atoms pointing towards the faces of the coordination octahedron. The heavier the metal atom, the smaller is the distance of the maxima from the atomic centre. These features are interpreted by a preferential occupation of the metal d orbitals which correspond to the cubic t2e orbitals. An analysis of the d-orbital populations indicates that the symmetry of the electron distribution around the metal atom is in all cases very close to cubic, the site symmetry being 3; the t2g orbitals appear to be fully occupied by six electrons while the occupation of the eg orbitals increases in the series Fe, Co, Ni and indicates covalent overlap with the S ligands.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Charge densities in CoS₂ and NiS₂ (pyrite structure)

Nowack¹,

Schwarzenbach²,

Hahn³

1991

Acta Crystallogr Sect B

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“…[14] In addition, nickel sulfides can form various phases, [15] such as NiS, Ni 3 + x S 2 , Ni 3 S 2 , Ni 7 S 6 , Ni 3 S 4 , and NiS 2 , and have multiple applications, including as photocatalysts for H 2 evolution, [16] possible transformation toughener, [17] cathode materials for rechargeable lithium batteries, [18] or as a highboiling solvent for all-solid-state lithium secondary batteries. [19] Furthermore, Du's group introduced the application of iron/ nickel sulfide filled carbon nanotubes and their microwave-absorbing properties, [20] with a maximum reflection loss of À29.58 dB.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Growth Mechanism of White‐Fungus‐Like Nickel Sulfide Microspheres, and Their Application in Polymer Composites with Enhanced Microwave‐Absorption Properties

Lü

Wang

et al. 2014

ChemPlusChem

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White‐fungus‐like NiSx microspheres have been synthesized on a large scale by using a simple hydrothermal method. The influence of the reaction time and the surfactant on the final products was investigated, and the formation mechanism was discussed. The synthesized white‐fungus‐like NiSx microspheres were used firstly as fillers in the fabrication of NiSx/polyvinylidene fluoride (PVDF) composites. Relationships between the loadings of the NiSx and wave‐absorption properties of the composites were analyzed. The loss mechanisms of NiSx/PVDF with different loadings were also discussed according to their dielectric and magnetic behaviors.

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“…In the Mott-Hubbard compound NiS 2−x Se x electron hoppings between the sites of Ni occur through the chalcogenide sites (this is caused by peculiarities of the pyrite crystal structure [33]), the substitution of S 2− ion for Se 2− ion in NiS 2 leads to an increase of wave functions overlap, consequently the probability of an electron hopping increases which is equivalent to a band broadening or to an external pressure increasing. Therefore, the pressure-temperature phase diagram constructed for NiS 2 can describe the experimental composition-temperature phase diagram [26,27] of the compound NiS 2−x Se x .…”

Section: Pressure-temperature Phase Diagram Of the Modelmentioning

confidence: 99%

Pressure-Temperature Phase Diagram of the Generalized Hubbard Model With Correlated Hopping at Half-Filling

Didukh¹,

Hankevych²

2001

Condens. Matter Phys.

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In the present paper, the pressure-temperature phase diagram of a generalized Hubbard model with correlated hopping in a paramagnetic state at half-filling is determined by means of a generalized mean-field approximation in the Green function technique. The constructed phase diagram describes the metal-to-insulator transition with increasing temperature, and the insulator-to-metal transition under the action of external pressure. The phase diagram can explain the paramagnetic region of the phase diagrams of some transition metal compounds.

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Electronic and magnetic properties of the pyrite-structure compound NiS₂: influence of vacancies and copper impurities

Cited by 72 publications

References 27 publications

Charge densities in CoS₂ and NiS₂ (pyrite structure)

Charge densities in CoS₂ and NiS₂ (pyrite structure)

Synthesis and Growth Mechanism of White‐Fungus‐Like Nickel Sulfide Microspheres, and Their Application in Polymer Composites with Enhanced Microwave‐Absorption Properties

Pressure-Temperature Phase Diagram of the Generalized Hubbard Model With Correlated Hopping at Half-Filling

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Electronic and magnetic properties of the pyrite-structure compound NiS2: influence of vacancies and copper impurities

Cited by 72 publications

References 27 publications

Charge densities in CoS2 and NiS2 (pyrite structure)

Charge densities in CoS2 and NiS2 (pyrite structure)

Synthesis and Growth Mechanism of White‐Fungus‐Like Nickel Sulfide Microspheres, and Their Application in Polymer Composites with Enhanced Microwave‐Absorption Properties

Pressure-Temperature Phase Diagram of the Generalized Hubbard Model With Correlated Hopping at Half-Filling

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Product

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Electronic and magnetic properties of the pyrite-structure compound NiS₂: influence of vacancies and copper impurities

Charge densities in CoS₂ and NiS₂ (pyrite structure)

Charge densities in CoS₂ and NiS₂ (pyrite structure)