Unconventional resistivity at the border of metallic antiferromagnetism inNiS2

Abstract

We report low-temperature and high-pressure measurements of the electrical resistivity ρ(T ) of the antiferromagnetic compound NiS2 in its high-pressure metallic state. The form of ρ(T ) suggests that metallic antiferromagnetism in NiS2 is quenched at a critical pressure pc = 76 ± 5 kbar. Near pc the temperature variation of ρ(T ) is similar to that observed in NiS2−xSex near the critical composition x = 1 where the Néel temperature vanishes at ambient pressure. In both cases ρ(T ) varies approximately as T 1.5 over a wide range below 100 K. However, on closer analysis the resistivity exponent in NiS2 exhibits an undulating variation with temperature not seen in NiSSe (x = 1). This difference in behaviour may be due to the effects of spin-fluctuation scattering of charge carriers on cold and hot spots of the Fermi surface in the presence of quenched disorder, which is higher in NiSSe than in stoichiometric NiS2.

Magnetic and metallic state at intermediate HubbardUcoupling in multiorbital models for undoped iron pnictides

“…61,62 Within dynamical mean-field theory, an AF-metallic state has also been discussed. 63 Experimentally, itinerant antiferromagnetic states were found in the pyrite NiS 2−x Se x , 64,65 in heavily doped manganites, 66 in ruthenates, 67 in organic conductors, 68,69 and in several other materials. An incommensurate spin density wave was also reported in metallic V 2−y O 3 .…”

Metal–insulator transition in NiS2−xSex: chemical vs external pressure effects

“…An MIT, induced by Se alloying (x), is observed at room temperature (RT) for x ∼ 0.6, and a magnetic phase boundary from an antiferromagnetic to a paramagnetic metal is found at a low temperature (T ) at x ∼ 1 (Figure 1(a)). An alternative way to induce a metallic state in NiS 2 is applying a hydrostatic P. A P-induced MIT was observed in pure NiS 2 for P > 4 GPa [4,5]. Whereas chemical substitution inevitably introduces impurities, changing many physical parameters in an incontrollable way, P offers a more systematic way of tuning the properties.…”

Shape evolution of NiS2 minicrystals via thermodynamic controlled growth

“…It has been widely known that the materials with specific microstructure, size and morphology take a significant part in their unique physical and chemical properties and potential applications in nanoscale devices [1][2][3][4]. Therefore, we have extensively investigated the morphology control and self-assembly methods to prepare nanomaterials with specific shapes and properties [5].…”

“…Therefore, we have extensively investigated the morphology control and self-assembly methods to prepare nanomaterials with specific shapes and properties [5]. Among them, nickel sulfide, as an important inorganic functional material, has attracted much attention because of practical applications, such as metal-insulator, paramagnetic-antiferromagnetic (PM-AFM) phase-changing material, magnetic refrigeration, magnetic resonance imaging and microwave absorption material [4]. Successes in shape control have been reported, such as nanorods [6], dodecahedron [7], nanotubes [8,9], 3D flowerlike [10,11] and urchin-like nanostructure [12].…”