Magnetic interaction parameters from paramagnetic diffuse neutron scattering in MnO

Hohlwein, D.; Hoffmann, J.-U.; Schneider, R.

doi:10.1103/physrevb.68.140408

Cited by 21 publications

(24 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The magnetic diffuse neutron-scattering cross section is directly proportional to the generalized wave-vector-dependent susceptibility tensor and thus measures the Fourier components of the microscopic magnetization fluctuations. 17 Such measurements have been reported in various magnetic systems [18][19][20][21][22] and the magnetic exchange interactions have been determined from the diffuse magnetic neutron-scattering cross sections. Although NiO is a prototype of a strongly correlated transition-metal oxide with a type-II antiferromagnetic structure, diffuse magnetic scattering investigation of NiO above the ordering temperature has not been reported so far.…”

mentioning

confidence: 99%

Antiferromagnetic phase transition and spin correlations in NiO

2009

View full text Add to dashboard Cite

We have investigated the antiferromagnetic ͑AF͒ phase transition and spin correlations in NiO by hightemperature neutron diffraction below and above T N . We show that AF phase transition is a continuous second-order transition within our experimental resolution. The spin correlations manifested by the strong diffuse magnetic scattering persist well above T N Ϸ 530 K and could still be observed at T = 800 K which is about 1.5T N . We argue that the strong spin correlations above T N are due to the topological frustration of the spins on a fcc lattice. The Néel temperature is substantially reduced by this process. We determined the critical exponents ␤ = 0.328Ϯ 0.002 and = 0.64Ϯ 0.03 and the Néel temperature T N = 530Ϯ 1 K. These critical exponents suggest that NiO should be regarded as a 3dXY system. DOI: 10.1103/PhysRevB.79.172403 PACS number͑s͒: 75.25.ϩz Transition-metal oxides have been the subject of renewed interest ever since high-temperature superconductivity was discovered in cuprate materials. The transition-metal oxides with narrow d bands form strongly correlated electron systems or a Mott-Hubbard system in which Coulomb interactions between electrons lead to a breakdown of the conventional band theory. In such a system, hole or electron doping may transform an insulating antiferromagnet into a highly correlated metal. 1,2 In selected copper oxides, the metal can superconduct, while in others it is a strongly renormalized Fermi liquid. In manganites for example the doping transforms the insulating antiferromagnet into a ferromagnetic metal with colossal magnetoresistive properties. 3 Among the transition-metal oxides the antiferromagnetic NiO plays a key role in the studies of the electronic and magnetic properties of correlated 3d-electron system. NiO, along with other transition-metal oxides MnO, FeO, and CoO, crystallizes with the face-centered-cubic ͑space group Fm3m͒ NaCl-type structure. The magnetic properties of pure NiO are well known. Ni 2+ ions in NiO are in an S = 1 state and order at T N = 530 K in the type-II antiferromagnetic structure with the propagation vector k = ͑ 1 2 , 1 2 , 1 2 ͒. Ferromagnetic ͑111͒ layers are antiferromagnetically stacked along the ͓111͔ direction. The magnetic moments of Ni lie in the ͑111͒ plane and there is now considerable evidence that they lie in the ͓1,1,−2͔ direction. 4 There is a rhombohedral distortion at T N which increases as the temperature is lowered. The electronic structure of NiO has been extensively investigated. [5][6][7] There are strong indications that NiO is a charge-transfer insulator 5 in which the top of the valence band is primarily formed by oxygen 2p states, while the bottom of the conduction band is Ni-3d like. The insulating state is characterized by a band gap of about 4 eV. Magnetic exchange interactions in NiO have been calculated 7-9 and have also been determined by measuring the spin-wave dispersion by inelastic neutron scattering. 10 The spin-wave dispersion in NiO could be described by a nearest-neighbor ͑NN͒ ferromag...

show abstract

mentioning

confidence: 99%

Antiferromagnetic phase transition and spin correlations in NiO

2009

View full text Add to dashboard Cite

show abstract

“…More recent studies of MnO single crystals have shown that short-range order of the Mn 2+ ions persists to high temperatures (around 6 × T N ). This short-range order has been studied by Hohlwein and co-workers [39], and analysed in terms of a mean-field model of the staggered susceptibility. However, since Hohlwein used unpolarized neutrons, his signal was contaminated with nuclear an incoherent scattering.…”

Section: Example 1: Paramagnetic Correlations In Mnomentioning

confidence: 99%

Disordered materials studied using neutron polarization analysis

Stewart

2007

Journées de la Neutronique

View full text Add to dashboard Cite

Abstract. The technique of longitudinal polarization analysis on a multi-detector ("xyz"-polarization analysis) is presented. This technique allows the simultaneous and unambiguous determination of the nuclear, magnetic and nuclear spin-incoherent scattering functions as a function of both momentum and energy transfer. Several examples of neutron polarization analysis studies of disordered systems are given, illustrating the valuable information which can be retrieved from the analysis of neutron scattering between the Bragg peaks.

show abstract

“…21,22 Previous neutron-scattering studies have shown that structured magnetic diffuse scattering is present above T N (Refs. 6,9,23) and short-range spin correlations persist to T 1100 K. 12,24 Yet, all previous measurements have been restricted to either individual reciprocal-space planes or the powder average, limiting the information content of the scattering pattern. 25 Advanced neutron-scattering instruments now allow measurement of essentially-complete threedimensional (3D) diffuse-scattering patterns, 26,27 but a key problem remains: analysis of these very large datasets is usually computationally prohibitive.…”

Section: Introductionmentioning

confidence: 99%

Magnetic structure of paramagnetic MnO

et al. 2018

View full text Add to dashboard Cite

Using a combination of single-crystal neutron scattering and reverse Monte Carlo refinements, we study the magnetic structure of paramagnetic MnO at a temperature (160 K) substantially below the Curie-Weiss temperature |θ| ∼ 550 K. The microscopic picture we develop reveals a locally-ordered domain structure that persists over distances many times larger than the correlation length implied by direct analysis of the spin correlation function. Moreover, the directional dependence of paramagnetic spin correlations in paramagnetic MnO differs in some important respects from that of its incipient ordered antiferromagnetic state. Our results have implications for the understanding of paramagnetic states in weakly-frustrated systems, including hightemperature superconductors.

show abstract

Magnetic interaction parameters from paramagnetic diffuse neutron scattering in MnO

Cited by 21 publications

References 11 publications

Antiferromagnetic phase transition and spin correlations in NiO

Antiferromagnetic phase transition and spin correlations in NiO

Disordered materials studied using neutron polarization analysis

Magnetic structure of paramagnetic MnO

Contact Info

Product

Resources

About