Thermal Expansion and Crystal Distortion of NiS<sub>2</sub>

Nagata, Hideo; Ito, Hajime; Miyadai, Tomonao

doi:10.1143/jpsj.41.2133

Cited by 22 publications

(7 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The magnetostrictive response of the lattice to M2 is likely rhombohedral 19 and the distortion from cubic symmetry is extremely small, with a relative lattice constant change ∆a/a ∼ 2 × 10 −4 (Ref. [20]). Therefore, for our diffraction measurements, we were able to model the insulating ground state using a cubic matrix.…”

Section: Antiferromagnetism At Ambient and High Pressuresmentioning

confidence: 99%

Magnetism, structure, and charge correlation at a pressure-induced Mott-Hubbard insulator-metal transition

et al. 2011

View full text Add to dashboard Cite

We use synchrotron x-ray diffraction and electrical transport under pressure to probe both the magnetism and the structure of single crystal NiS2 across its Mott-Hubbard transition. In the insulator, the low-temperature antiferromagnetic order results from superexchange among correlated electrons and couples to a (1/2, 1/2, 1/2) superlattice distortion. Applying pressure suppresses the insulating state, but enhances the magnetism as the superexchange increases with decreasing lattice constant. By comparing our results under pressure to previous studies of doped crystals we show that this dependence of the magnetism on the lattice constant is consistent for both band broadening and band filling. In the high pressure metallic phase the lattice symmetry is reduced from cubic to monoclinic, pointing to the primary influence of charge correlations at the transition. There exists a wide regime of phase separation that may be a general characteristic of correlated quantum matter.

show abstract

Section: Antiferromagnetism At Ambient and High Pressuresmentioning

confidence: 99%

Magnetism, structure, and charge correlation at a pressure-induced Mott-Hubbard insulator-metal transition

et al. 2011

View full text Add to dashboard Cite

show abstract

“…The phase transition at T N2 is accompanied by small lattice distortion. 28,29 This small crystal distortion therefore appears to break lattice symmetry and relieve spin frustration. Figure 10 shows the temperature dependence of the Q-scan spectra at the type-I AF Bragg point for a characteristic energy of 12 meV (ϷJ).…”

Section: Inelastic Neutron Scatteringmentioning

confidence: 99%

Classical and quantum spin dynamics in the fcc antiferromagnetNiS2with frustration

et al. 2003

View full text Add to dashboard Cite

The unusual coexistence of two antiferromagnetic ͑AF͒ long-range orderings ͑LRO͒ in single-crystal NiS 2 is investigated through measurements of inelastic neutron scattering, specific heat, uniform magnetic susceptibility, and resistivity. Neutron scattering intensity reveals a honeycomb pattern of the intensity distribution in reciprocal lattice space ͑continuous-line structure along the Brillouin zone boundaries͒ in the extended critical temperature region (T N1 ϭ39.3 KϽTϽ150 K) providing direct evidence for nearly frustrated antiferromagnetism on the face centered cubic ͑fcc͒ lattice. The observed geometrical pattern of the critical scattering makes it possible to determine the exchange coupling constants between the first, second, and third nearest neighbors, which are found to be consistent with LDAϩU band calculation. The system is found to be located very close to the phase boundary between the type-I AF state with Q AF ϭ(1,0,0), and the type-II AF state with Q AF ϭ͑1/2,1/2,1/2͒. Theoretical analysis based on the Onsager reaction field reproduces the various features in experiments at a semiquantitative level. The type-I AF order appears the highest Néel temperature T N1 ϭ39.3 K, while at T N2 ϭ30.6 K, the type-I and type-II AF LRO coexist via a first-order phase transition accompanied by a small but finite lattice distortion. This coexistence is explained in terms of coupling between the spin and lattice in the nearly degenerate case, although the type-I and type-II AF LRO become mutually incompatible in the fcc symmetry at higher temperatures. The AF LRO and lattice distortion lift the degeneracy and the accumulation of spectral weight at low energy, recovering the quantum nature ͑spin-wave excitation͒ of the spin fluctuation.

show abstract

“…19) A small structural distortion below T N2 has been reported. 21,22) The Curie-Weiss temperature W estimated from the high-T susceptibility is about 1250 K. 23) Strong magnetic frustration is evident from the large frustration parameter, f ¼ W =T N1 $ 30. The M1 ordered state (T N2 < T ≦ T N1 ) is known to host the noncoplanar antiferromagnetic (NAF) spin structure with four spin sublattices, 19) similarly to the AIAO structure [ Fig.…”

mentioning

confidence: 99%

“…2 Synchrotron X-ray and thermal expansion measurements revealed that a small distortion accompanies the WF-phase transition. 21,22) While the full spin structure has not yet been clarified in the WF-phase, it was proposed that the WF moment originates from a slight canting in the [100] direction. 19,21) Thus, because the weak ferromagnetism arises from the spin canting induced by the structural phase transition across T N2 , the FC operation may stabilize a single WF-domain if there is a strong magnetoelastic coupling.…”

mentioning

confidence: 99%

Magnetization Anomaly due to the Non-Coplanar Spin Structure in NiS₂

Higo

Nakatsuji

2015

J. Phys. Soc. Jpn.

View full text Add to dashboard Cite

The pyrite-type antiferromagnet NiS 2 exhibits a non-coplanar antiferromagnetic (NAF) spin ordering with four spin sublattices in the temperature region between T N1 = 38 K and T N2 = 30 K, and forms a weak ferromagnetic phase below T N2 . We have carried out detailed magnetization measurements using high-quality single crystals of NiS 2 to reveal magnetic properties associated with the NAF spin structure. Our results obtained in the field cooling sequence under various magnetic fields μ 0 H FC reveal that the magnetic domains due to the NAF structure may be controlled through the field cooling procedure into the low-temperature weak ferromagnetic phase. Unusual μ 0 H FC dependence of the magnetic hysteresis found in the NAF ordered phase strongly suggests that the weak ferromagnetic moment comes from the domain wall.Non-coplanar spin arrangements in frustrated magnets have attracted great interest because the associated vector and=or scalar spin chirality may induce exotic phenomena such as multiferroicity, 1) topological Hall transport, 2-4) and chiral spin liquid states. 3,5) While most non-coplanar magnets are characterized by their ferromagnetic (FM) component, a purely antiferromagnetic (AF) all-in=all-out (AIAO) structure (all moments on a tetrahedron point either inwards or outwards to its center) has recently been discovered in several 5d transition metal pyrochlore oxides such as Eu 2 Ir 2 O 7 , 6-8) Nd 2 Ir 2 O 7 , 9) and Cd 2 Os 2 O 7 . 10) While this magnetic structure has zero net magnetic moment owing to the cancellation of the moments on the four vertexes of a tetrahedron, it has two types of AF variant, which are connected by the time-reversal operation, and permits a multi-domain state as in the case of ferromagnetism. The domain wall (DW) breaks such a constraint and thus may alter the electronic structure locally. 11) In particular, the AIAO state in the Ir system is interesting because various topologically nontrivial states such as Weyl semimetals and topological Mott insulators have been predicted to arise on the basis of the interplay of Coulomb interactions, spin-orbit coupling, and the topology of band structure. 12-15) In addition, it has been theoretically proposed 16) that the magnetic domain hosts a gapless interface state with Fermi arcs and induces net uniform magnetization as the origin of the spin-glass-like magnetic signature observed in various pyrochlore iridates. 6,17) Experimentally, the anomalous magnetoconductivity and the unconventional weak ferromagnetic (WF) moment realized in the AIAO ordered phase have been observed in Nd 2 Ir 2 O 7 18) and Eu 2 Ir 2 O 7 . 6) As the domain physics is inherent to the AIAO structure, similarly interesting physics associated with the DW should generally emerge in other materials that host the AIAO structure. However, to date, there have been almost no reports on studies of domain phenomena related to the AIAO structure.The AF insulator NiS 2 has the pyrite structure (Pa " 3; T 6 h ) where Ni and S pairs form the NaCl structure. The magne...

show abstract

Thermal Expansion and Crystal Distortion of NiS₂

Cited by 22 publications

References 6 publications

Magnetism, structure, and charge correlation at a pressure-induced Mott-Hubbard insulator-metal transition

Magnetism, structure, and charge correlation at a pressure-induced Mott-Hubbard insulator-metal transition

Classical and quantum spin dynamics in the fcc antiferromagnetNiS2with frustration

Magnetization Anomaly due to the Non-Coplanar Spin Structure in NiS₂

Contact Info

Product

Resources

About

Thermal Expansion and Crystal Distortion of NiS2

Cited by 22 publications

References 6 publications

Magnetism, structure, and charge correlation at a pressure-induced Mott-Hubbard insulator-metal transition

Magnetism, structure, and charge correlation at a pressure-induced Mott-Hubbard insulator-metal transition

Classical and quantum spin dynamics in the fcc antiferromagnetNiS2with frustration

Magnetization Anomaly due to the Non-Coplanar Spin Structure in NiS2

Contact Info

Product

Resources

About

Thermal Expansion and Crystal Distortion of NiS₂

Magnetization Anomaly due to the Non-Coplanar Spin Structure in NiS₂