Energy dispersive x-ray diffraction of charge density waves via chemical filtering

Feng, Yejun; Somayazulu, Maddury; Jaramillo, Rafael; Rosenbaum, T. F.; Isaacs, E. D.; Hu, Jingzhú; Mao, H. K.

doi:10.1063/1.1938954

Cited by 19 publications

(19 citation statements)

References 20 publications

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“…9,10 Steady progress has pushed the achievable sensitivity to about 10 −9 . 11,12 The small dimensions of DAC are also perfectly suited for experiments at low temperatures. A disadvantage of the DAC technique can be the small sample size, typically below 100 m in diameter and 20 m in thickness, which makes it more sensitive to surface effects.…”

Section: Introductionmentioning

confidence: 99%

A clamp-type pressure cell for high energy x-ray diffraction

Zimmermann

Nowak

et al. 2008

Review of Scientific Instruments

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We present a clamp-type pressure cell for high energy x-ray diffraction. The pressure cell was specifically designed for studies of weak superstructure reflections at low temperatures in transition metal oxides, resulting from, e.g., charge density modulations. Using a photon energy of E = 100 keV, the bulk properties of single crystals with a volume of typically 2 -5 mm 3 can be studied in transmission geometry. To demonstrate the performance of the pressure cell, we present data on the charge stripe order in the high-temperature superconductor La 1.875 Ba 0.125 CuO 4 .

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Section: Introductionmentioning

confidence: 99%

A clamp-type pressure cell for high energy x-ray diffraction

Zimmermann

Nowak

et al. 2008

Review of Scientific Instruments

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“…For low temperature measurements, the DAC was loaded in a He flown cryostat, in which temperature was measured with a thermocouple with an accuracy of ± 2 K. Additional experimental details about beamline 11-ID-C and 16-BMD can be found in Refs. [15,16]. To facilitate measurement of the diffuse scattering signal, the sample was rocked ± 6 • in omega.…”

mentioning

confidence: 99%

Origin of diffuse scattering in relaxor ferroelectrics

et al. 2010

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High-pressure and variable temperature single crystal synchrotron X-ray measurements combined with first-principles based molecular dynamics simulations study diffuse scattering in the relaxor ferroelectric system PSN (PbSc 1/2 Nb 1/2 O3). Constant temperature experiments show pressure induced transition to the relaxor phase at different temperatures characterized by butterfly and rod shaped diffuse scattering around the {h00} and {hh0} Bragg spots, respectively. The simulations reproduce the observed diffuse scattering features as well as their pressure-temperature behavior, and show that they arise from polarization correlations between chemically-ordered regions, which in previous simulations were shown to behave as polar nanoregions. Simulations also exhibit radial diffuse scattering (elongated towards and away from Q=(000)), that persists even in the paraelectric phase, consistent with previous neutron experiments on (PbMg 1/3 Nb 2/3 O3) (PMN).Single crystal relaxors have huge electromechanical coupling, and show much promise for ultrasonic transducer applications [1]. They have broad frequency and temperature dependent dielectric maxima, which in the special case of relaxor-ferroelectrics [2,3] drops to a much lower value below the ferroelectric transition temperature (T F E ). The origin of the relaxor phase has been a topic of intense research for over a decade. From refractive index measurements, Burns et al. [4] suggested that formation of polar clusters below a characteristic temperature, now called the Burns temperature (T d ) [4], gives rise to dielectric dispersion, which was confirmed experimentally [5]. These clusters thought to be a few nanometers in size are called polar nanoregions (PNRs).Recent X-ray and neutron experiments show characteristic shapes of diffuse scattering in the relaxor phase of several lead based relaxors [6,7,8,9] absent in their paraelectric or ferroelectric phases. The main observed feature is anisotropic diffuse scattering around the Bragg peaks along <110> directions. The ferroelectric phase shows weak streaks similar to BaTiO 3 and KNbO 3 , but rotated by 45-degrees. The paraelectric phase only shows radial diffuse scattering.Several hypotheses previously advanced to explain the characteristic shapes [6,10,11,12], invoke some type of artificial anisotropic features such as anisotropic strain, correlated atomic shifts, or domain boundaries to generate the experimentally observed anisotropic diffuse scattering features. Fitting the shapes of diffuse scattering features is not sufficient to uniquely determine the nature of the microstructural feature that give rise to them. Incorporating realistic polarization fluctuations via first-principles derived models provide a basis for clarifying the nature of the PNR in relaxors and experimental diffuse scattering observations provide a critical test for any theoretical model. In this Letter, we clarify the microstructural origin of diffuse scattering features in the relaxor-and the paraelectric-phases of PSN, and related materi...

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“…Additional experimental details about the beamline can be found in Ref. 27; further information on the Raman scattering setup as well as the procedures can be found in Refs. 24 and 28.…”

Section: Methodsmentioning

confidence: 99%

Structural transitions in Pb(In1∕2Nb1∕2)O₃ under pressure

et al. 2015

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Room-temperature Raman scattering and x-ray diffraction measurements together with first-principles calculations were employed to investigate the behavior of disordered Pb(In 1=2 Nb 1=2 ÞO 3 (PIN) under pressure up to 50 GPa. Raman spectra show broad bands but a peak near the 380 cm À1 increases its intensity with pressure. The linewidth of the band at 550 cm À1 also increases with pressure, while two of the Raman peaks merge above 6 GPa. Above 16 GPa, we observe additional splitting of the band at 50 cm À1 . The pressure evolution of the diffraction patterns for PIN shows obvious Bragg peaks splitting above 16 GPa; consistent with a symmetry lowering transition. The transition at 0.5 GPa is identified as a pseudo-cubic to orthorhombic (Pbam) structural change whereas the transition at 16 GPa is isostructure and associated with changes in linear compressibility and octahedral titling, and the transition at 30 GPa is associated to an orthorhombic to monoclinic change. First-principles calculations indicate that the Pbam structure is ground state with antiferrodisdortion consistent with experiment.

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Energy dispersive x-ray diffraction of charge density waves via chemical filtering

Cited by 19 publications

References 20 publications

A clamp-type pressure cell for high energy x-ray diffraction

A clamp-type pressure cell for high energy x-ray diffraction

Origin of diffuse scattering in relaxor ferroelectrics

Structural transitions in Pb(In1∕2Nb1∕2)O₃ under pressure

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Energy dispersive x-ray diffraction of charge density waves via chemical filtering

Cited by 19 publications

References 20 publications

A clamp-type pressure cell for high energy x-ray diffraction

A clamp-type pressure cell for high energy x-ray diffraction

Origin of diffuse scattering in relaxor ferroelectrics

Structural transitions in Pb(In1∕2Nb1∕2)O3 under pressure

Contact Info

Product

Resources

About

Structural transitions in Pb(In1∕2Nb1∕2)O₃ under pressure