Neutron Scattering Investigation of Phase Transitions and Magnetic Correlations in the Two-Dimensional Antiferromagnets<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">K</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>Ni<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">F</mml:mi></mml:mrow><mml:mrow>

Birgeneau, R. J.; Guggenheim, H. J.; Shirane, G.

doi:10.1103/physrevb.1.2211

Cited by 358 publications

(103 citation statements)

References 30 publications

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“…In Fig.6 our results for the staggered magnetization are shown together with the experimental data from Ref. 22 and the interpolating curve there proposed. Besides the overall agreement in the whole ordered phase, it is to be noticed that our prediction for the value of the critical temperature perfectly coincides with the one deriving from the experimental analysis, which gives T c = 38.4 K (i.e.…”

Section: Comparison With Experimental Datamentioning

confidence: 95%

“…As for a more precise quantitative analysis, we have concentrated ourselves on the S = 5/2 magnet Rb 2 MnF 4 : reason for this choice is the availability of recent neutron scattering data 6 relative to such compound and the fact that, because of its cristallographic structure, Rb 2 MnF 4 is known to behave as a two-dimensional magnet both above and below the observed transition 22,25 . This means that the critical behaviour is not contaminated by the onset of three-dimensional order and a clean characterization of the transition is possible, as well as a meaningful comparison with the experimental data for the magnetization below T c .…”

Section: Comparison With Experimental Datamentioning

confidence: 99%

“…The magnetic structure of layered real compounds is such that the exchange integral J for neighbouring spins belonging to the same plane is orders of magnitude larger than that for neighbouring spins on different planes [20][21][22] , hereafter called J ′ ; one would hence naively expect the magnetic properties to be those of an effective two-dimensional magnet down to temperatures of the order of J ′ , until the transition towards an ordered three-dimensional phase should take place. However, the experimentally observed transition occurs at a critical temperature of the order of J, signalling the transition itself to be driven by the intra-layer exchange interaction; details of such interaction, such as possible easyaxis or easy-plane anisotropies, are hence fundamental in the analysis of the critical behaviour.…”

Section: Introductionmentioning

confidence: 99%

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Finite-temperature ordering in two-dimensional magnets

et al. 2000

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We study the two dimensional quantum Heisenberg antiferromagnet on the square lattice with easyaxis exchange anisotropy. By the semiclassical method called pure-quantum self-consistent harmonic approximation we analyse several thermodynamic quantities and investigate the existence of a finite temperature transition, possibly describing the low-temperature critical behaviour experimentally observed in many layered real compounds. We find that an Ising-like transition characterizes the model even when the anisotropy is of the order of 10 −2 J (J being the intra-layer exchange integral), as in most experimental situations. On the other hand, typical features of the isotropic Heisenberg model are observed for both values of anisotropy considered, one in the quasi-isotropic limit and the other in a more markedly easy-axis region. The good agreement found between our theoretical results and the experimental data relative to the real compound Rb2MnF4 shows that the insertion of the easy-axis exchange anisotropy, with quantum effects properly taken into account, provides a quantitative description and explanation of the experimental data, thus allowing to recognize in such anisotropy the main agent for the observed onset of finite temperature long-range order.

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Section: Comparison With Experimental Datamentioning

confidence: 95%

Section: Comparison With Experimental Datamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Finite-temperature ordering in two-dimensional magnets

et al. 2000

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“…23,24 The analyzer was removed thus ensuring that any two-dimensional diffuse scattering along L at finite energy transfers maintains the specified inplane H value ͑Fig. 1͒.…”

Section: Magnetic Scattering In Bafe 2 Asmentioning

confidence: 99%

Antiferromagnetic critical fluctuations inBaFe2As2

et al. 2010

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Magnetic correlations near the magnetostructural phase transition in the bilayer iron-pnictide parent compound, BaFe 2 As 2 , are measured. In close proximity to the antiferromagnetic phase transition in BaFe 2 As 2 ,a crossover to three-dimensional critical behavior is anticipated and has been preliminarily observed. Here we report complementary measurements of two-dimensional magnetic fluctuations over a broad temperature range about T N . The potential role of two-dimensional critical fluctuations in the magnetic phase behavior of BaFe 2 As 2 and their evolution near the anticipated crossover to three-dimensional critical behavior and longrange order are discussed.

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“…This effect can be compared with the magnetic diffuse scattering on KzNiF 4 observed by Plumier (1964), who attributed it to the stacking faults of magnetic layers. In fact, as was later shown (Birgenau, Guggenheim & Shirane, 1970;Heger & Geller, 1972) the observed diffuse scattering was caused by twodimensional short-range order. The low dimension-ality of such systems is not a consequence of the crystal-structure disorder, but results from the domination of the intra-layer magnetic interaction owing to the large separation of layers and/or cancellation effects (de Jong & Miedema, 1974).…”

Section: (B) Magnetic Diffuse Scatteringmentioning

confidence: 50%