Quasistationary criticality of the order parameter of the three-dimensional random-field Ising antiferromagnet<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mi mathvariant="normal">Fe</mml:mi><mml:mn>0.85</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">Zn</mml:mi><mml:mn>0.15</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">F</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>: A synchrotron x-ray scattering study

Ye, F.; Zhou, Long; Meyer, Sibylle; Shelton, Leslie J.; Belanger, D. P.; Li, Lu; Larochelle, S.; Greven, M.

doi:10.1103/physrevb.74.144431

Cited by 12 publications

(13 citation statements)

References 42 publications

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“…It is rather comparable to temperature scalings observed for 8CB in aerogels or pSi [2]. The observation of a low β value for a continuous transition is in fact not unusual, and is observed in the case of dilute antiferromagnets or disordered ferroelectrics [19,20], which are prototypical realizations of the three dimensional random field Ising model (3DRFIM).…”

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confidence: 76%

Criticality of an isotropic-to-smectic transition induced by anisotropic quenched disorder

et al. 2010

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We report combined optical birefringence and neutron scattering measurements on the liquid crystal 12CB nanoconfined in mesoporous silicon layers. This liquid crystal exhibits strong nematicsmectic coupling responsible for a discontinuous isotropic-to-smectic phase transition in the bulk state. Confined in porous silicon, 12CB is subjected to strong anisotropic quenched disorder: a shortranged smectic state evolves out of a paranematic phase. This transformation appears continuous, losing its bulk first order character. This contrasts with previously reported observations on liquid crystals under isotropic quenched disorder. In the low temperature phase, both orientational and translational order parameters obey the same power-law.PACS numbers: 64.70. Nd, 61.30.Eb Since its introduction in 1975 by Imry and Ma [1], the influence of random fields on phase transitions has been one of the most debated topics in condensed matter physics. Various realizations of this phenomenology could be achieved by confining liquid crystals (LCs) in geometrically disordered porous materials or gels [2][3][4]. In principle, the geometric restriction introduces two forms of disorder in LCs: random orientational fields that couple to the nematic director and random positional fields that couple to the smectic order. Studies on the influence of these couplings while varying the magnitude of disorder and its isotropic or anisotropic character has largely contributed to recent progress in the understanding of quenched disorder (QD) effects on phase transitions in LCs [2,5,6]. Owing to their generic character, these findings are also relevant to many other systems, most prominently for supraconductors or for superfluids [7].Both the second order nematic-smectic A (N-SmA) and normal-superconducting transitions can be mapped onto each other and, in principle, fall in the universality class of the 3D XY model [7,8], since both can be described by a complex order parameter representing the amplitude and phase of a sinusoidal-varying smectic mass density wave or a macroscopic wave function, respectively. However, as was pointed out first by de Gennes the coupling between nematic (Q) and smectic (η) order parameters (OPs) actually takes the N-SmA transition away from that class. Conversely, increasing the strength of isotropic QD can gradually shift the character of the NSmA transition from tricritical back to 3D XY universality. This was verified by studies on n-octyl-cyanobiphenyl (8CB) in aerogels or loaded with random dispersions of aerosil particles [3,4]. For these systems, the influence of strong isotropic QD in the weak Q-η coupling limit was addressed. For anisotropic QD, this striking effect is already visible in the limit of weak disorder strength in the case of 8CB. Following the argumentation of Garland and Iannachione [4], this suggests that the Q-η coupling is reduced by isotropic QD, and is even entirely turned off by anisotropic QD.An interesting test of this hypothesis was made by Ramazoglu et. al.[8] on the 10CB/aerosil co...

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confidence: 76%

Criticality of an isotropic-to-smectic transition induced by anisotropic quenched disorder

et al. 2010

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“…This is of paramount importance for materials for which model Hamiltonians are currently either unknown or under debate. For example, Fe 0.85 Zn 0.15 F 2 is a diluted antiferromagnet in a field 35,36 which is expected to be well described by a random-field Ising model. 5,6 Currently experiments as well as simulations are being performed to characterize this material/model using the FORC method.…”

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confidence: 99%

Finite versus zero-temperature hysteretic behavior of spin glasses: Experiment and theory

et al. 2007

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We present experimental results attempting to fingerprint nonanalyticities in the magnetization curves of spin glasses found by Katzgraber et al. [Phys. Rev. Lett. 89, 257202 (2002)] via zerotemperature Monte Carlo simulations of the Edwards-Anderson Ising spin glass. Our results show that the singularities at zero temperature due to the reversal-field memory effect are washed out by the finite temperatures of the experiments. The data are analyzed via the first order reversal curve (FORC) magnetic fingerprinting method. The experimental results are supported by Monte Carlo simulations of the Edwards-Anderson Ising spin glass at finite temperatures which agree qualitatively very well with the experimental results. This suggests that the hysteretic behavior of real Ising spinglass materials is well described by the Edwards-Anderson Ising spin glass. Furthermore, reversalfield memory is a purely zero-temperature effect.

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“…However, most experimental studies focus on diluted antiferromagnets in a field (DAFF), such as Fe x Zn 1−x F 2 . 3,[12][13][14][15] Fishman and Aharony 16 were the first to note that a random antiferromagnet in a field can be described by the RFIM, and Cardy 17 predicted, using a mean-field argument, that the critical behavior of both models should be in the same universality class in the limit of small fields. The work of Fishman and Aharony, 16 as well as Cardy, 17 therefore opened the door for intense experimental investigation of the RFIM via DAFF materials.…”

Section: Introductionmentioning

confidence: 99%

Diluted antiferromagnets in a field seem to be in a different universality class than the random-field Ising model

Ahrens,

Xiao,

Hartmann

et al. 2013

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We perform large-scale Monte Carlo simulations using the Machta-Newman-Chayes algorithms to study the critical behavior of both the diluted antiferromagnet in a field with 30% dilution and the random-field Ising model with Gaussian random fields for different field strengths. Analytical calculations by Cardy [Phys. Rev. B 29, 505 (1984)] predict that both models map onto each other and share the same universality class in the limit of vanishing fields. However, a detailed finite-size scaling analysis of the Binder cumulant, the two-point finite-size correlation length, and the susceptibility suggests that even in the limit of small fields, where the mapping is expected to work, both models are not in the same universality class. Based on our numerical data, we present analytical expressions for the phase boundaries of both models.

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Quasistationary criticality of the order parameter of the three-dimensional random-field Ising antiferromagnetFe0.85Zn0.15F2: A synchrotron x-ray scattering study

Cited by 12 publications

References 42 publications

Criticality of an isotropic-to-smectic transition induced by anisotropic quenched disorder

Criticality of an isotropic-to-smectic transition induced by anisotropic quenched disorder

Finite versus zero-temperature hysteretic behavior of spin glasses: Experiment and theory

Diluted antiferromagnets in a field seem to be in a different universality class than the random-field Ising model

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