A neutron scattering investigation of the order of the magnetic transition in NiO

Doorn, C.F. van; Plessis, P. de V. du

doi:10.1016/0375-9601(78)90020-8

Cited by 20 publications

(5 citation statements)

References 14 publications

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“…This result agrees with the studies of the nature of magnetic transition in NiO by the neutron scattering investigation as well as magnetic susceptibility measurements, references [22] and [23], respectively.…”

Section: Resultssupporting

confidence: 91%

Magnetic Ordering in Polycrystalline NixZn1?xO Solid Solutions

Rodić¹,

Spasojević²,

Kusigerski³

et al. 2000

phys. stat. sol. (b)

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In order to examine the influence of the dilution of magnetic ions on the crystal and magnetic structure of NixZn1—xO (x = 1, 0.90, 0.80, 0.70) solid solutions we have performed neutron diffraction experiments on each sample at seven temperatures between 10 and 295 K. To determine the Néel temperatures, the magnetic susceptibility measurements were done in the temperature region between room temperature and 600 K. Starting from the known rhombohedral distortion the crystal structure has been refined in the trigonal space group R3¯m. In this space group the cations occupy octahedral 3a position (with the local symmetry 3¯m), while the oxygen anion is placed in the 3b position (with the local symmetry 3¯m). The magnetic structure for all concentrations x is found to be antiferromagnetic and the magnetic cell is the doubled nuclear cell along the c‐axis. The magnetic atoms are arranged in the planes (003) in respect to the nuclear cell. The magnetic moments of two Ni2+ ions in adjacent sheets are oriented antiparallely and the magnetic vector makes an angle of 66° with the c‐axis. The magnetic structure is preserved upon random site dilution of the magnetic ions. This is additionally confirmed from the Brillouin‐type dependence of the magnetization on temperature as well as from the t = TN(x)/TN(1) versus x variation obtained from the magnetic susceptibility measurements. Concentration dependence of the Néel temperature also shows that NixZn1—xO behaves like a Heisenberg antiferromagnet with the dominant nearest‐neighbor interaction, in agreement with the similar (Ni, Co)xMg1—xO solid solution.

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Section: Resultssupporting

confidence: 91%

Magnetic Ordering in Polycrystalline NixZn1?xO Solid Solutions

Rodić¹,

Spasojević²,

Kusigerski³

et al. 2000

phys. stat. sol. (b)

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“…If the space group Fm3m is accepted as the true space group of the paramagnetic phase then subgroup±group relation for R " 3m and Fm3m space groups leads to the conclusion that the phase transition at the Ne Â el point is of the second order. This result agrees with the studies of the nature of magnetic transition in NiO by the neutron scattering investigation as well as magnetic susceptibility measurements, references [22] and [23], respectively.…”

Section: Resultssupporting

confidence: 91%

Magnetic Ordering in Polycrystalline NixZn1xO Solid Solutions

Rodić¹,

Spasojević²,

Kusigerski³

et al. 2000

phys. stat. sol. (b)

View full text Add to dashboard Cite

In order to examine the influence of the dilution of magnetic ions on the crystal and magnetic structure of Ni x Zn 1Àx O (x 1, 0.90, 0.80, 0.70) solid solutions we have performed neutron diffraction experiments on each sample at seven temperatures between 10 and 295 K. To determine the Ne Â el temperatures, the magnetic susceptibility measurements were done in the temperature region between room temperature and 600 K. Starting from the known rhombohedral distortion the crystal structure has been refined in the trigonal space group R " 3m. In this space group the cations occupy octahedral 3a position (with the local symmetry " 3m), while the oxygen anion is placed in the 3b position (with the local symmetry " 3m). The magnetic structure for all concentrations x is found to be antiferromagnetic and the magnetic cell is the doubled nuclear cell along the c-axis. The magnetic atoms are arranged in the planes (003) in respect to the nuclear cell. The magnetic moments of two Ni 2 ions in adjacent sheets are oriented antiparallely and the magnetic vector makes an angle of 66 with the c-axis. The magnetic structure is preserved upon random site dilution of the magnetic ions. This is additionally confirmed from the Brillouin-type dependence of the magnetization on temperature as well as from the t T N xaT N 1 versus x variation obtained from the magnetic susceptibility measurements. Concentration dependence of the Ne Â el temperature also shows that Ni x Zn 1Àx O behaves like a Heisenberg antiferromagnet with the dominant nearest-neighbor interaction, in agreement with the similar (Ni, Co) x Mg 1Àx O solid solution.

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“…Our present experimental results suggest a second-order continuous transition within experimental resolution. This is more complete and precise than previous measurements by van Doorn and DuPlessis, 30 who also concluded the transition was continuous.…”

Section: ͑2͒supporting

confidence: 57%

“…The intensity of this reflection decreases continuously with increasing temperature and becomes zero at about T N Ϸ 530 K. Our present experimental results show that the intensity of the 1 2 1 2 1 2 magnetic reflection of NiO varies continuously within our experimental resolution, which is better than in previous measurements. 30 The data just below T N could be fitted by a power-law exponent…”

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confidence: 99%

Antiferromagnetic phase transition and spin correlations in NiO

2009

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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...

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A neutron scattering investigation of the order of the magnetic transition in NiO

Cited by 20 publications

References 14 publications

Magnetic Ordering in Polycrystalline NixZn1?xO Solid Solutions

Magnetic Ordering in Polycrystalline NixZn1?xO Solid Solutions

Magnetic Ordering in Polycrystalline NixZn1xO Solid Solutions

Antiferromagnetic phase transition and spin correlations in NiO

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