Near-surface domain structures in uniaxially stressed

Chrosch, J.; Salje, Ekhard K. H.

doi:10.1088/0953-8984/10/13/002

Cited by 50 publications

(41 citation statements)

References 36 publications

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“…Its experimental check can be then an effective way to distinguish between genuine fluctuation-driven critical behaviour and pure Landau behaviour. Indeed, this proportionality relation has recently been shown for SrTiO 3 , in contradiction with a common belief that this compound exhibits in a significant temperature interval asymptotic critical behaviour corresponding to the Heisenberg-3D or the Ising-3D universality class [6,7,8]. The analysis of ∆s, instead of checking directly the expected critical behaviour of the excess specific heat ∆c, has the fundamental advantage of using an integrated quantity with a smooth temperature dependence that is independent of experimental statistical errors in the measurement of ∆c.…”

Section: Introductionmentioning

confidence: 64%

The order parameter entropy relation in some universal classes: experimental evidence

Martín‐Olalla

Romero

Ramos

et al. 2003

J. Phys.: Condens. Matter

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The asymptotic behaviour near phase transitions can be suitably characterized by the scaling of ∆s/Q 2 with ǫ = 1 − T /T c , where ∆s is the excess entropy and Q is the order parameter. As ∆s is obtained by integration of the experimental excess specific heat of the transition ∆c, it displays little experimental noise so that the curve log(∆s/Q 2 ) versus log ǫ is better constrained than, say, log ∆c versus log ǫ. The behaviour of ∆s/Q 2 for different universality classes is presented and compared. In all cases, it clearly deviates from being a constant. The determination of this function can then be an effective method to distinguish asymptotic critical behaviour. For comparison, experimental data for three very different systems, Rb 2 CoF 4 , Rb 2 ZnCl 4 and SrTiO 3 , are analysed under this approach. In SrTiO 3 , the function ∆s/Q 2 does not deviate within experimental resolution from a straight line so that, although Q can be fitted with a non mean-field exponent, the data can be explained by a classical Landau mean-field behaviour. In contrast, the behaviour of ∆s/Q 2 for the antiferromagnetic transition in Rb 2 CoF 4 and the normal-incommensurate phase transition in Rb 2 ZnCl 4 is fully consistent with the asymptotic critical behaviour of the universality class corresponding to each case. This analysis supports, therefore, the claim that incommensurate phase transitions in general, and the A 2 BX 4 compounds in particular, in contrast with most structural phase transitions, have critical regions large enough to be observable.

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Section: Introductionmentioning

confidence: 64%

The order parameter entropy relation in some universal classes: experimental evidence

Martín‐Olalla

Romero

Ramos

et al. 2003

J. Phys.: Condens. Matter

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“…X-ray diffraction methods have proved to be a powerful tool to study twinning microstructures and their associated domain boundaries, provided care is taken to optimize the collection and processing of the diffraction signal (Chrosch & Salje, 1994Wruck et al, 1994;Locherer et al, 1998). Reciprocal-space studies (that is, diffraction rather than microscopy) are preferable since, although each individual twin boundary occupies a tiny volume (and hence will give a very small experimental signal), diffraction experiments allow for the superposition of the signals from a large number of essentially identical twin walls.…”

Section: Theoretical Basismentioning

confidence: 99%

“…By studying the evolution of the twin wall signal with temperature, the temperature dependence of w has been studied in a disordered (Na, K) feldspar and the ferroelastic perovskite LaAlO 3 (Chrosch & Salje, 1999). In both these systems, the predicted behaviour w G jT À T C j À1/2 was observed.…”

Section: Theoretical Basismentioning

confidence: 99%

“…6 shows the temperature dependence of these quantities in LaAlO 3 , as measured by Harrison et al (2004). There is a dramatic softening of LaAlO 3 below 823 K, associated with the onset of twinning at the cubic±rhombohedral phase transition (Chrosch & Salje, 1999). On cooling, LaAlO 3 remains superelastic over a wide temperature range.…”

Section: Domain Walls and Anelasticitymentioning

confidence: 99%

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Ferroelastic phase transitions: structure and microstructure

Salje

Hayward

Lee

2004

Acta Crystallogr A Found Crystallogr

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Landau-type theories describe the observed behaviour of phase transitions in ferroelastic and co-elastic minerals and materials with a high degree of accuracy. In this review, the derivation of the Landau potential G = 1 2 A S [coth( S /T) À coth( S /T C )]Q 2 + 1 4 BQ 4 + F F F is derived as a solution of the general 0 4 model. The coupling between the order parameter and spontaneous strain of a phase transition brings the behaviour of many phase transitions to the mean-®eld limit, even when the atomistic mechanism of the transition is spin-like. Strain coupling is also a common mechanism for the coupling between multiple order parameters in a single system. As well as changes on the crystal structure scale, phase transitions modify the microstructure of materials, leading to anomalous mesoscopic features at domain boundaries. The mesostructure of a domain wall is studied experimentally using X-ray diffraction, and interpreted theoretically using Ginzburg±Landau theory. One important consequence of twin mesostructures is their modi®ed transport properties relative to the bulk. Domain wall motion also provides a mechanism for superelastic behaviour in ferroelastics. At surfaces, the relaxations that occur can be described in terms of order parameters and Landau theory. This leads to an exponential pro®le of surface relaxations. This in turn leads to an exponential interaction energy between surfaces, which can, if large enough, destabilize symmetrical morphologies in favour of a platelet morphology. Surface relaxations may also affect the behaviour of twin walls as they intersect surfaces, since the surface relaxation may lead to an incompatibility of the two domains at the surface, generating large strains at the relaxation. Landau theory may also be extended to describe the kinetics of phase transitions. Time-dependent Landau theory may be used to describe the kinetics of order±disorder phase transitions in which the order parameter is homogeneous. However, the time-dependent Landau theory equations also have microstructural solutions, explaining the formation of microstructures such as tweed.

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“…The polar properties are still dominated by Ti with the underlying ferroelastic twin structures being extremely sensitive to external forces. The great mobility of twin walls in SrTiO3 was documented by Kityk et al [83,84], and the high density of twin walls and dislocations near the crystal surface was shown by X-ray diffraction [85] and optical microscopy [86]. Wall polarity was observed by resonant piezoelectric spectroscopy (RPS) [13,21] at temperatures well below the ferroelastic phase transition [87].…”

Section: Srtiomentioning

confidence: 94%

Ferroelastic Domain Boundary-Based Multiferroicity

Salje

Ding

2016

Crystals

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Domain boundary engineering endeavors to develop materials that contain localized functionalities inside domain walls, which do not exist in the bulk. Here we review multiferroic devices that are based on ferroelectricity inside ferroelastic domain boundaries. The discovery of polarity in CaTiO 3 and SrTiO 3 leads to new directions to produce complex domain patterns as templates for ferroic devices.

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Near-surface domain structures in uniaxially stressed

Cited by 50 publications

References 36 publications

The order parameter entropy relation in some universal classes: experimental evidence

The order parameter entropy relation in some universal classes: experimental evidence

Ferroelastic phase transitions: structure and microstructure

Ferroelastic Domain Boundary-Based Multiferroicity

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