Suppression of the cooperative Jahn-Teller distortion and its effect on the Raman octahedra-rotation modes of 
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Vilarinho, R.; Passos, D. J.; Queirós, E. C.; Tavares, Pedro B.; Almeida, A.; Weber, Mads C.; Guennou, Maël; Kreisel, J.; Moreira, J. Agostinho

doi:10.1103/physrevb.97.144110

Cited by 15 publications

(16 citation statements)

References 29 publications

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“…Substitution of Mn 3+ by Fe 3+ has been of interest because it allows, in principle, tuning of the contribution of Jahn-Teller cooperative distortions [53][54][55][56]. The two cations have closely similar radii but Fe 3+ is not Jahn-Teller active.…”

Section: Sample Descriptionmentioning

confidence: 99%

Strain relaxation dynamics of multiferroic orthorhombic manganites

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O’Flynn

et al. 2021

J. Phys.: Condens. Matter

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Resonant Ultrasound Spectroscopy has been used to characterise strain coupling and relaxation behaviour associated with magnetic/magnetoelectric phase transitions in GdMnO3, TbMnO3 and TbMn0.98Fe0.02O3 through their influence on elastic/anelastic properties. Acoustic attenuation ahead of the paramagnetic → colinear-sinusoidal/incommensurate/antiferromagnetic transition at ~41 K correlates with anomalies in dielectric properties and is interpreted in terms of Debye-like freezing processes. A loss peak at ~150 K is related to a steep increase in electrical conductivity with a polaron mechanism. The activation energy, Ea, of ≥ ~0.04 eV from a loss peak at ~80 K is consistent with the existence of a well-defined temperature interval in which the paramagnetic structure is stabilised by local, dynamic correlations of electric and magnetic polarisation that couple with strain and have relaxation times in the vicinity of ~10 -6 s. Comparison with previously published data for Sm0.6Y0.4MnO3 confirms that this pattern may be typical for multiferroic orthorhombic RMnO3 perovskites (R = Gd, Tb, Dy). A frequencydependent loss peak near 10 K observed for TbMnO3 and TbMn0.98Fe0.02O3, but not for GdMnO3, yielded Ea ≥ ~0.002 eV and is interpreted as freezing of some magnetoelastic component of the cycloid structure. Small anomalies in elastic properties associated with the incommensurate and cycloidal magnetic transitions confirm results from thermal expansion data that the magnetic order parameters have weak but significant coupling with strain. Even at strain magnitudes of ~0.1-1 ‰, polaron-like strain effects are clearly important in defining the development and evolution of magnetoelectric properties in these materials. Strains associated with the cubicorthorhombic transition due to the combined Jahn-Teller/octahedral tilting transition in the vicinity of 1500 K are 2-3 orders of magnitude greater. It is inevitable that ferroelastic twin walls due to this transition would have significantly different magnetoelectric properties from homogeneous domains due to magnetoelastic coupling with steep strain gradients.

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Section: Sample Descriptionmentioning

confidence: 99%

Strain relaxation dynamics of multiferroic orthorhombic manganites

Carpenter

Pesquera

O’Flynn

et al. 2021

J. Phys.: Condens. Matter

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“…In the case of RMnO3, three very distinct Mn-O distances are found, due to the Jahn-Teller effect. Figure 6(b) presents a schematic c-axis view of these bonds and tilt angles of the RMnO3 structure [33] . The Mn-O medium bond length is always along the b-direction, while the short and long bond lengths are staggered on the ac-plane.…”

Section: Pm-3m Pnmamentioning

confidence: 99%

“…Within these conditions, the chemical substitution can be divided into 2 groups: substitution of the A-site cation and substitution of the B-site cation. The first type of chemical substitution allows for the tuning of the tilt distortion [45] , while the second one is associated with the octahedra distortion [33] . In the past, the effect of changing the tilt distortion was extensively studied by A-site substitution in rare-earth manganites [45][46][47][48][49][50][51][52][53][54][55][56][57][58][59] .…”

Section: Continuously Tuning the Jahn-teller Distortionmentioning

confidence: 99%

“…To study the effect of changing the Jahn-Teller distortion, we have followed the work of Vilarinho et al on TbMn1-xFexO3. Figure 12 presents the x-dependence of the five symmetry-adapted modes for this system [33] . We focus on the amplitude of the M2+ distortion, associated with the BO6 octahedra deformation.…”

Section: Continuously Tuning the Jahn-teller Distortionmentioning

confidence: 99%

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Structural distortions of orthorhombic RFeO3 and RMnO3

2021

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We will address in detail the structural distortions responsible for the symmetry lowering of the ideal cubic Pm-3m perovskite to the orthorhombic Pnma structure of RFeO3 and RMnO3 (R = trivalent rare-earth cation), important to the stabilization of the different magnetic and multiferroic phases in these materials. We will also show how the Amplimodes tool of Bilbao Crystallographic Server is useful in quantifying these distortions and establish which phonons can be used as probes of both the octahedra tilting and deformation.

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“…This difference can easily be understood using the same logical reasoning as before by taking into account that the Jahn-Teller distortion present in RMnO3 provides an additional pressure accommodation mechanism than in their respective RFeO3 compounds. It is worth to note that the tilt angles for RFeO3 and RMnO3, with the same rare-earth ion, are almost the same, thus allowing for this comparison [15].…”

Section: High-pressure Phase Transitionmentioning

confidence: 99%

Investigating the anisotropic compression and high-pressure phase symmetry of orthorhombic RFeO₃ vs RMnO₃

2020

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Rare-earth orthoferrites and orthomanganites present strong couplings between their structural distortions and physical properties, namely magnetoelectricity, generating interest in predicting and realizing new phases under external parameters, such as hydrostatic pressure. In this regard, we discuss the differences and the similarities of the high-pressure behaviour of the structural distortions arising from anisotropic volume compression. This allows a better understanding of the role played by the octahedra tilt and Jahn-Teller effect as pressure accommodation mechanisms on the stabilization of different crystallographic phases after the insulator to metal structural transition occurring at the critical pressures (Pc) between 35 and 50 GPa.

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Suppression of the cooperative Jahn-Teller distortion and its effect on the Raman octahedra-rotation modes of TbMn1−xFexO

Cited by 15 publications

References 29 publications

Strain relaxation dynamics of multiferroic orthorhombic manganites

Strain relaxation dynamics of multiferroic orthorhombic manganites

Structural distortions of orthorhombic RFeO3 and RMnO3

Investigating the anisotropic compression and high-pressure phase symmetry of orthorhombic RFeO₃ vs RMnO₃

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Suppression of the cooperative Jahn-Teller distortion and its effect on the Raman octahedra-rotation modes of TbMn1−xFexO

Cited by 15 publications

References 29 publications

Strain relaxation dynamics of multiferroic orthorhombic manganites

Strain relaxation dynamics of multiferroic orthorhombic manganites

Structural distortions of orthorhombic RFeO3 and RMnO3

Investigating the anisotropic compression and high-pressure phase symmetry of orthorhombic RFeO3 vs RMnO3

Contact Info

Product

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Investigating the anisotropic compression and high-pressure phase symmetry of orthorhombic RFeO₃ vs RMnO₃