Structural Phase Transition Nomenclature. Report of an IUCr Working Group on Phase Transition Nomenclature

Tolédano, J. C.; Glazer, A. M.; Hahn, Th.; Parthé, E.; Roth, R. S.; Berry, R. Stephen; Metselaar, R Ruud; Abrahams, S. C.

doi:10.1107/s0108767398008150

Cited by 20 publications

(10 citation statements)

References 12 publications

(13 reference statements)

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“…S1. 1 èukaszewicz & Karat-Kalicin Â ska's (1974) data, taken provi-sionally as more reliable, clearly show a decrease ($0.028 A Ê ) in the c axis between 300 and 1075 K, with much smaller lattice constant discontinuities in the range 895±955 K, in contrast to Ismailzade & Kizhaev's (1965) results, which indicate a discontinuous increase ($0.021 A Ê ) in the c-axis dimension between 300 and 935 K. The recommended nomenclature of Tole Â dano et al (1998) The atomic coordinates for phase II | < 1270 K of van Aken et al (2001a), 2 or their symmetry equivalents, are given in Table 1 with an origin shift in z of 0.2505 to minimize AEÁz [by setting Áz(Y1) + Áz(Y2) + Áz(Mn) = 0]; Áz as used in (1) is de®ned below. A view of the YMnO 3 structure, which differs signi®cantly from that of perovskite, may be found in Fig.…”

Section: Ferroelectric Ymnomentioning

confidence: 83%

Ferroelectricity and structure in the YMnO₃ family

Abrahams¹

2001

Acta Crystallogr B Struct Sci

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116

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The 1963 discovery of ferroelectricity in YMnO(3) was accompanied by an experimental Curie temperature (T(c)) reported as 913 K; this value was revised to 1270 K in the following decade. Subsequently, YInO(3) was shown to be isostructural with YMnO(3) and later demonstrated to satisfy the structural criteria for ferroelectricity; recent unpublished measurements give T(c) (YInO(3)) = 835 (15) K. The experimental T(c) value of 913 K for YMnO(3) is in satisfactory agreement with the calculated 1220 (100) K value as derived from a very recent structural refinement, the experimental T(c) of 835 (15) K for YInO(3) with the calculated 760 (120) K. The full YMnO(3) family includes the AMnO(3) subfamily with A = Y, Ho, Er, Tm, Yb, Lu, Sc, In; the AInO(3) subfamily with A = Y, Gd, Dy, Ho, Tb; and the AGaO(3) subfamily with A = Y, Ho, Er. The T(c) values of six family members with known structure, in addition to YMnO(3) and YInO(3), have been structurally derived as 1310 (110) K for ErMnO(3), 1290 (165) K for LuMnO(3), 1270 (110) K for YbMnO(3), 1220 (105) K for ScMnO(3), 540 (375) K for InMnO(3) and 1020 (100) K for YGaO(3). The agreement between predicted and experimental T(c) values for ErMnO(3), LuMnO(3) and YbMnO(3), in addition to that for YMnO(3) and YInO(3), leads to the confident prediction that ScMnO(3), InMnO(3) and YGaO(3) are new ferroelectrics. The remaining six members of the full YMnO(3) family are also expected to be new ferroelectrics.

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Section: Ferroelectric Ymnomentioning

confidence: 83%

Ferroelectricity and structure in the YMnO₃ family

Abrahams¹

2001

Acta Crystallogr B Struct Sci

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116

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“…Nomenclature of Polymorphs. ± The −Report of an IUCr Working Group on Phase Transition Nomenclature× (Tole¬dano et al [31]) provides background information and a proposal for a −Six-field phasetransition nomenclature×. This proposal has the virtue of completeness but the deficiencies of not distinguishing enantiotropic and monotropic systems 12 ), and of using only inorganic substances as illustrative examples.…”

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Towards a Complete Description of a Polymorphic Crystal: The Example of Perylene

Botoshansky

Herbstein

Kapon

2003

Helvetica Chimica Acta

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Crystal structures of the two polymorphs of perylene have been determined at low temperatures (150 and 200 K), and the molecular geometry was compared with earlier crystallographic and NMR measurements. Cell dimensions have been measured for both polymorphs over the ranges 150–320 K for (EI‐β) and 150–420 K for (EII‐α). Combination of thermodynamic and crystallographic measurements has permitted inference of pressuretemperature phase diagrams for perylene and pyrene that are compatible with available measurements up to ca. 50 kbar. Perylene and pyrene are both enantiotropic systems, while phenazine appears to be monotropic.

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“…Finally, x14 demonstrates that a signi®cant change in atomic positions is caused by replacing even minor proportions of Al in the Pb 5 Al 3 F 19 structure by a 3d element. The recommended IUCr nomenclature (Tole Â dano et al, 1998) for the lowest temperature phase is V j`260 KjI4cm 108jZ 4j ferroelectricj2 variantsY in which the transition temperature here and throughout x1 is that measured on heating. The next-highest temperature phase is IV j315À260 KjP4an 85jZ 8jantiferroelectricj2 variantsX The remaining pure phase for which the structure has been reported is IIj670-360 KjI4am 87jZ 4jparaelasticj2 variants differing in elastic propertiesX…”

Section: Introductionmentioning

confidence: 99%

Structure–property correlation over five phases and four transitions in Pb₅Al₃F₁₉

Abrahams

Ravez

Ritter

et al. 2003

Acta Crystallogr Sect B

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The calorimetric and dielectric properties of Pb(5)Al(3)F(19) in the five phases stable under ambient pressure are correlated with structure for fuller characterization of each phase. The first-order transition between ferroelectric phase V and antiferroelectric phase IV at T(V,IV) = 260 (5) K exhibits a thermal hysteresis of 135 (5) K on heating, with a maximum atomic displacement Delta(xyz)(max) = 1.21 (6) A; the transition from phase IV to ferroelastic phase III at 315 (5) K is also first order but with a thermal hysteresis of 10 (5) K and Delta(xyz)(max) = 0.92 (7) A; that from phase III to paraelastic phase II at 360 (5) K is second order without hysteresis and has Delta(xyz)(max) = 0.69 (4) A; and the transition from phase II to paraelectric phase I at 670 (5) K is second or higher order, with Delta(xyz)(max) = 0.7 (4) A. The measured entropy change DeltaS at T(V,IV) agrees well with DeltaS as derived from the increased configurational energy by Stirling's approximation. For all other phase transitions, 0.5 > or = DeltaS > 0 J mol(-1) K(-1) is consistent with an entropy change caused primarily by the changes in the vibrational energy. The structure of phase III is determined both by group theoretical/normal mode analysis and by consideration of the structures of phases II, IV and V reported previously; refinement is by simultaneous Rietveld analysis of the X-ray and neutron diffraction powder profiles. The structure of prototypic phase I is predicted on the basis of the atomic arrangement in phases II, III, IV and V. The introduction of 3d electrons into the Pb(5)Al(3)F(19) lattice disturbs the structural equilibrium, the addition of 0.04% Cr(3+) causing significant changes in atomic positions and increasing T(IV,III) by approximately 15 K. Substitution of Al(3+) by 20% or more Cr(3+) eliminates the potential minima that otherwise stabilize phases IV, III and II.

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Structural Phase Transition Nomenclature. Report of an IUCr Working Group on Phase Transition Nomenclature

Cited by 20 publications

References 12 publications

Ferroelectricity and structure in the YMnO₃ family

Ferroelectricity and structure in the YMnO₃ family

Towards a Complete Description of a Polymorphic Crystal: The Example of Perylene

Structure–property correlation over five phases and four transitions in Pb₅Al₃F₁₉

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Structural Phase Transition Nomenclature. Report of an IUCr Working Group on Phase Transition Nomenclature

Cited by 20 publications

References 12 publications

Ferroelectricity and structure in the YMnO3 family

Ferroelectricity and structure in the YMnO3 family

Towards a Complete Description of a Polymorphic Crystal: The Example of Perylene

Structure–property correlation over five phases and four transitions in Pb5Al3F19

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Product

Resources

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Ferroelectricity and structure in the YMnO₃ family

Ferroelectricity and structure in the YMnO₃ family

Structure–property correlation over five phases and four transitions in Pb₅Al₃F₁₉