Elastic coupling and anelastic relaxation associated with multiple phase transitions in para-chloroanilinium tetrachlorocuprate, [p-ClC6H4NH3]2CuCl4

Thomson, Richard I.; Rawson, Jeremy M.; Goeta, Andrés E.; Probert, Michael R.; Coome, J. A.; Hoang, Tuan K.A.; Carpenter, Michael A.

doi:10.1016/j.matchemphys.2012.11.031

Cited by 8 publications

(6 citation statements)

References 37 publications

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“…These changes were linked to differences in the packing arrangements adopted by these molecules within the organic bilayer (Figure D), thus highlighting the importance of the organic cation in templating the inorganic lattice . Other studies have emphasized the importance of factors including the steric demands of the organic cation, hydrogen-bonding influences, ,− and the charge density of the alkylammonium head , as well as its proximity to the plane of the inorganic sheets in templating the inorganic lattice.…”

Section: Structurementioning

confidence: 91%

Tuning the Luminescence of Layered Halide Perovskites

2019

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Layered halide perovskites offer a versatile platform for manipulating light through synthetic design. Although most layered perovskites absorb strongly in the ultraviolet (UV) or near-UV region, their emission can range from the UV to the infrared region of the electromagnetic spectrum. This emission can be very narrow, displaying high color purity, or it can be extremely broad, spanning the entire visible spectrum and providing high color rendition (or accurately reproducing illuminated colors). The origin of the photoluminescence can vary enormously. Strongly correlated electron−hole pairs, permanent lattice defects, transient light-induced defects, and ligand-field transitions in the inorganic layers and molecular chromophores in the organic layers can be involved in the emission mechanism. In this review, we highlight the different types of photoluminescence that may be attained from layered halide perovskites, with an emphasis on how the emission may be systematically tuned through changes to the bulk crystalline lattice: changes in composition, structure, and dimensionality.

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Section: Structurementioning

confidence: 91%

Tuning the Luminescence of Layered Halide Perovskites

2019

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“…In this context equation (A.1) merely provides a convenient description of reducing slope as T → 0 K, which is comparable in form to a description by the Varshni equation (e.g. see [52]). Data for Q −1 , the excess of Q −1 with respect to a straight line fit to values above ∼50 K, have been added to figure 4, excluding high values that were due to saturation of the amplifier.…”

Section: Strain Analysis Order Parameter Evolution and Elastic Soften...mentioning

confidence: 99%

CoF₂: a model system for magnetoelastic coupling and elastic softening mechanisms associated with paramagnetic ↔ antiferromagnetic phase transitions

Thomson

Chatterji

Carpenter

2014

J. Phys.: Condens. Matter

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Resonant ultrasound spectroscopy has been used to monitor variations in the elastic and anelastic behaviour of polycrystalline CoF2 through the temperature interval 10-290 K and in the frequency range ∼0.4-2 MHz. Marked softening, particularly of the shear modulus, and a peak in attenuation occur as the Néel point (TN=39 K) is approached from both high and low temperatures. Although the effective thermodynamic behaviour can be represented semiquantitatively with a Bragg-Williams model for a system with spin 1/2, the magnetoelastic coupling follows a pattern which is closely analogous to that of a Landau tricritical transition which is co-elastic in character. Analysis of lattice parameter data from the literature confirms that linear spontaneous strains scale with the square of the magnetic order parameter and combine to give effective shear and volume strains on the order of 1‰. Softening of the shear modulus at T>TN is attributed to coupling of acoustic modes with dynamical local ordering of spins and can be represented by a Vogel-Fulcher expression. At T

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“…A convenient baseline has the form of equation (.12), which has been fitted to f 2 data for ErCo 2 between 173 and 291 K and extrapolated to 0 K ( figure 11(a)). This gives essentially the same description as the equation of Varshni [67] for elastic moduli at low temperatures [68,69]. To estimate a baseline for NdCo 2 , which has f 2 almost independent of temperature above ∼500 K, it was simpler to use low temperature data for the shear modulus of YCo 2 , which does not display magnetic ordering, taken from Klimker et al [18].…”

Section: Softening Mechanisms In the Stability Range Of The Cubic Phasesmentioning

confidence: 99%

Multiferroic (ferroelastic/ferromagnetic/ferrimagnetic) aspects of phase transitions in RCo₂Laves phases

Driver

Herrero‐Albillos

Bonilla

et al. 2014

J. Phys.: Condens. Matter

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Magnetic phase transitions in RCo 2 Laves phases with R as a rare earth element are accompanied by changes in crystallographic space group. For purely structural transitions they would be described as improper ferroelastic and therefore fulfil the condition for multiferroic phase transitions in combining two out of three properties, ferro/antiferromagnetism, ferroelectricity and ferroelasticity. Here lattice parameter data from the literature and new measurements of elastic and anelastic properties, by resonant ultrasound spectroscopy, for NdCo 2 and ErCo 2 have been analysed from this perspective. The temperature dependence of symmetry-breaking shear strains is consistent with the cubic ↔ tetragonal transition in NdCo 2 being close to tricritical in character and the cubic ↔ rhombohedral transition in ErCo 2 being first order. Elastic softening and acoustic loss within the stability ranges of the ferroelastic phases can be understood in terms of a combination of intrinsic softening due to strain/order parameter coupling and ferroelastic twin-wall motion. Softening ahead of the transitions does not fit with standard macroscopic descriptions of dynamic effects from other systems but, rather, in the case of NdCo 2 , might be attributed to the involvement of a second zone centre order parameter related to a separate instability driven by cooperative Jahn-Teller distortions. In ErCo 2 , acoustic loss in the temperature interval above the transition point is discussed in terms of a possible tweed microstructure associated with strain coupling to local magnetic ordering. The overall multiferroic behaviour can be understood in terms of a single magnetic order parameter (irrep m + 4 of magnetic space group Fd3m1 ) which couples with a structural order parameter (irrep + 3 or + 5 ). The coupling is linear/quadratic which, in the case of two separate instabilities, causes them to combine in a single multiferroic phase transition.

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Elastic coupling and anelastic relaxation associated with multiple phase transitions in para-chloroanilinium tetrachlorocuprate, [p-ClC6H4NH3]2CuCl4

Cited by 8 publications

References 37 publications

Tuning the Luminescence of Layered Halide Perovskites

Tuning the Luminescence of Layered Halide Perovskites

CoF₂: a model system for magnetoelastic coupling and elastic softening mechanisms associated with paramagnetic ↔ antiferromagnetic phase transitions

Multiferroic (ferroelastic/ferromagnetic/ferrimagnetic) aspects of phase transitions in RCo₂Laves phases

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Elastic coupling and anelastic relaxation associated with multiple phase transitions in para-chloroanilinium tetrachlorocuprate, [p-ClC6H4NH3]2CuCl4

Cited by 8 publications

References 37 publications

Tuning the Luminescence of Layered Halide Perovskites

Tuning the Luminescence of Layered Halide Perovskites

CoF2: a model system for magnetoelastic coupling and elastic softening mechanisms associated with paramagnetic ↔ antiferromagnetic phase transitions

Multiferroic (ferroelastic/ferromagnetic/ferrimagnetic) aspects of phase transitions in RCo2Laves phases

Contact Info

Product

Resources

About

CoF₂: a model system for magnetoelastic coupling and elastic softening mechanisms associated with paramagnetic ↔ antiferromagnetic phase transitions

Multiferroic (ferroelastic/ferromagnetic/ferrimagnetic) aspects of phase transitions in RCo₂Laves phases