Origin of the non-linear pressure effects in perovskite manganites: Buckling of Mn–O–Mn bonds and Jahn–Teller distortion of the MnO6 octahedra induced by pressure

Chen, Z.; Tyson, Trevor; Ahn, K. H.; Zhong, Z.; Hu, Jingshi

doi:10.1016/j.jmmm.2010.05.027

Cited by 11 publications

(5 citation statements)

References 18 publications

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“…tetragonal strain, e t , as has been observed in single crystals belonging to the LaAlO 3 -PrAlO 3 solid solution, where the Jahn-Teller active cation is Pr 3+ [41,68]. Related softening of shear elastic moduli is observed also in (Pr, Ca)MnO 3 [69][70][71][72], and (La, Ca)MnO 3 [73][74][75][76][77] but has not been observed in LaCoO 3 (this study). On the other hand, the C2/c structure can also develop by combining R-point tilting with a Jahn-Teller order parameter which transforms as the irreducible representation R + 3 , and which corresponds to the a-type ordering of KCuF 3 [78].…”

Section: Strain Analysis and Possible Elastic Softening/stiffening Me...supporting

confidence: 72%

Strain coupling mechanisms and elastic relaxation associated with spin state transitions in LaCoO₃

Zhang¹,

Koppensteiner²,

Schranz³

et al. 2011

J. Phys.: Condens. Matter

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Advantage is taken of the wealth of experimental data relating to the evolution with temperature of spin states of Co(3+) in LaCoO₃ in order to undertake a detailed investigation of the mechanisms by which changes in electronic structure can influence strain, and elastic and anelastic relaxations in perovskites. The macroscopic strain accompanying changes in the spin state in LaCoO₃ is predominantly a volume strain arising simply from the change in effective ionic radius of the Co(3+) ions. This acts to renormalize the octahedral tilting transition temperature in a manner that is easily understood in terms of coupling between the tilt and spin order parameters. Results from resonant ultrasound spectroscopy at high frequencies (0.1-1.5 MHz) reveal stiffening of the shear modulus which scales qualitatively with a spin order parameter defined in terms of changing Co-O bond lengths. From this finding, in combination with results from dynamic mechanical analysis at low frequencies (0.1-50 Hz) and data from the literature, four distinctive anelastic relaxation mechanisms are identified. The relaxation times of these are displayed on an anelasticity map and are tentatively related to spin-spin relaxation, spin-lattice relaxation, migration of twin walls and migration of magnetic polarons. The effective activation energy for the freezing of twin wall motion below ~590 K at low frequencies was found to be 182 ± 21 kJ mol(-1) (1.9 ± 0.2 eV) which is attributed to pinning by pairs of oxygen vacancies, though the local mechanisms appear to have a spread of relaxation times. It seems inevitable that twin walls due to octahedral tilting must have quite different characteristics from the matrix in terms of local spin configurations of Co(3+). A hysteresis in the elastic properties at high temperatures further emphasizes the importance of oxygen content in controlling the properties of LaCoO₃.

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Section: Strain Analysis and Possible Elastic Softening/stiffening Me...supporting

confidence: 72%

Strain coupling mechanisms and elastic relaxation associated with spin state transitions in LaCoO₃

Zhang¹,

Koppensteiner²,

Schranz³

et al. 2011

J. Phys.: Condens. Matter

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“…Here, the variance of Ag-Te distances, K , is used to quantify the distortion of coordination polyhedron30. Based on the Ag-Te distances of P 2 1 / c phase in Supplementary Table S2, the pressure dependence of K in P 2 1 / c phase is shown in the Supplementary Fig.…”

Section: Resultsmentioning

confidence: 99%

Electronic Topological Transition in Ag2Te at High-pressure

Zhang

et al. 2015

Sci Rep

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Recently, Ag2Te was experimentally confirmed to be a 3D topological insulator (TI) at ambient pressure. However, the high-pressure behaviors and properties of Ag2Te were rarely reported. Here, a pressure-induced electronic topological transition (ETT) is firstly found in Ag2Te at 1.8 GPa. Before ETT, the positive pressure coefficient of bulk band-gap, which is firstly found in TIs family, is found by both first-principle calculations and in situ high-pressure resistivity measurements. The electrical resistivity obtained at room temperature shows a maximum at 1.8 GPa, which is nearly 3.3 times to that at ambient pressure. This result indicates that the best bulk insulating character and topological nature in Ag2Te can be obtained at this pressure. Furthermore, the high-pressure structural behavior of Ag2Te has been investigated by in situ high-pressure synchrotron powder X-ray diffraction technique up to 33.0 GPa. The accurate pressure-induced phase transition sequence is firstly determined as P21/c → Cmca → Pnma. It is worth noting that the reported isostructural P21/c phase is not existed, and the reported structure of Cmca phase is corrected by CALYPSO methodology. The second high-pressure structure, a long puzzle to previous reports, is determined as Pnma phase. A pressure-induced metallization in Ag2Te is confirmed by the results of temperature-dependent resistivity measurements.

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“…S7b †), consistent with earlier reports. 58,59 The onset potential for oxygen evolution in Sr doped GBCO was found to be $1.50 to 1.52 V with respect to the reversible hydrogen electrode (RHE). This is approximately 50-70 mV earlier than that for the undoped GBCO (1.57 V) as determined by linear sweep voltammetry with scanning rate of 1 mV s À1 performed on static electrodes (Fig.…”

Section: Conductivity and Electrochemical Performancementioning

confidence: 99%

Crystal structure and surface characteristics of Sr-doped GdBaCo₂O_6−δ double perovskites: oxygen evolution reaction and conductivity

Pramana

Cavallaro

et al. 2018

J. Mater. Chem. A

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Origin of the non-linear pressure effects in perovskite manganites: Buckling of Mn–O–Mn bonds and Jahn–Teller distortion of the MnO6 octahedra induced by pressure

Cited by 11 publications

References 18 publications

Strain coupling mechanisms and elastic relaxation associated with spin state transitions in LaCoO₃

Strain coupling mechanisms and elastic relaxation associated with spin state transitions in LaCoO₃

Electronic Topological Transition in Ag2Te at High-pressure

Crystal structure and surface characteristics of Sr-doped GdBaCo₂O_6−δ double perovskites: oxygen evolution reaction and conductivity

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Origin of the non-linear pressure effects in perovskite manganites: Buckling of Mn–O–Mn bonds and Jahn–Teller distortion of the MnO6 octahedra induced by pressure

Cited by 11 publications

References 18 publications

Strain coupling mechanisms and elastic relaxation associated with spin state transitions in LaCoO3

Strain coupling mechanisms and elastic relaxation associated with spin state transitions in LaCoO3

Electronic Topological Transition in Ag2Te at High-pressure

Crystal structure and surface characteristics of Sr-doped GdBaCo2O6−δ double perovskites: oxygen evolution reaction and conductivity

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Strain coupling mechanisms and elastic relaxation associated with spin state transitions in LaCoO₃

Strain coupling mechanisms and elastic relaxation associated with spin state transitions in LaCoO₃

Crystal structure and surface characteristics of Sr-doped GdBaCo₂O_6−δ double perovskites: oxygen evolution reaction and conductivity