High pressure x-ray diffraction studies on nanocrystalline materials

Pałosz, B.; Stelmakh, S.; Grzanka, Ewa; Gierlotka, S.; Pielaszek, Roman; Bismayer, U.; Werner, Stephan; Pałosz, W.

doi:10.1088/0953-8984/16/5/003

Cited by 55 publications

(50 citation statements)

References 64 publications

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“…It was shown that even simple elements under pressure can undergo surprising transformations to structures where the atoms differentiate into a host and a guest network (Nelmes et al, 1999;McMahon et al, 2000). Pressure and temperature can also be used for inducing amorphous phases of various compounds or for investigating properties of nanoparticles (Palosz et al, 2004).…”

Section: Strained Crystals Molecules and Atomsmentioning

confidence: 99%

High-pressure crystallography

Katrusiak

2007

Acta Crystallogr A Found Crystallogr

169

128

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Since the late 1950's, high-pressure structural studies have become increasingly frequent, following the inception of opposed-anvil cells, development of efficient diffractometric equipment (brighter radiation sources both in laboratories and in synchrotron facilities, highly efficient area detectors) and procedures (for crystal mounting, centring, pressure calibration, collecting and correcting data). Consequently, during the last decades, high-pressure crystallography has evolved into a powerful technique which can be routinely applied in laboratories and dedicated synchrotron and neutron facilities. The variation of pressure adds a new thermodynamic dimension to crystal-structure analyses, and extends the understanding of the solid state and materials in general. New areas of thermodynamic exploration of phase diagrams, polymorphism, transformations between different phases and cohesion forces, structureproperty relations, and a deeper understanding of matter at the atomic scale in general are accessible with the high-pressure techniques in hand. A brief history, guidelines and requirements for performing high-pressure structural studies are outlined.

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Section: Strained Crystals Molecules and Atomsmentioning

confidence: 99%

High-pressure crystallography

Katrusiak

2007

Acta Crystallogr A Found Crystallogr

169

128

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“…(A.7) thatR b (h 0 , 0) does not depend on the considered Bragg reflection h 0 . Therefore, we can write 14) and the proportionality constant can be evaluated by Eq. (A.7) with ∆q = 0.…”

Section: Appendix: Error Evaluationmentioning

confidence: 99%

“…In the most complex cases, non-crystallographic structures 2,3,4,5,6,7,8,9,10,11 may occur. Surface-related deformation fields 12,13,14 are another challenge. In these extreme cases, the classical crystallographic formalism becomes quite useless.…”

Section: Introductionmentioning

confidence: 99%

Nanoparticle size distribution estimation by a full-pattern powder diffraction analysis

et al. 2005

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The increasing scientific and technological interest in nanoparticles has raised the need for fast, efficient and precise characterization techniques. Powder diffraction is a very efficient experimental method, as it is straightforward and non-destructive. However, its use for extracting information regarding very small particles brings some common crystallographic approximations to and beyond their limits of validity. Powder pattern diffraction calculation methods are critically discussed, with special focus on spherical particles with log-normal distribution, with the target of determining size distribution parameters. A 20-nm CeO2 sample is analyzed as example.

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“…Palosz et al [4] also used a two-phase model to interpret their diffraction data for SiC, GaN, and diamond nanoparticles. The concept of an "apparent lattice parameter" clearly indicates strong deviations of the position of Bragg peaks (especially at small angles) from the predicted crystallographic positions.…”

Section: Problem Of the Structural Diversity Of The Nanoworldmentioning

confidence: 99%

Nanostructures with coherent boundaries and the local approach

et al. 2004

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In our recent works [1,2], we analyzed the structural diversity of nanoparticles and the fragmentariness of their structure and formulated the statement that the structural inhomogeneity is a fundamental property of the nanostate. This statement was experimentally confirmed for a number of materials.In particular, reasoning from the results of neutron diffraction and X-ray diffraction investigations of ZrO 2 nanoparticles, Burkhanov et al. [3] proposed a twophase model allowing for the difference between the central and peripheral regions of a particle and their pseudomorphic conjugation. Palosz et al. [4] also used a two-phase model to interpret their diffraction data for SiC, GaN, and diamond nanoparticles. The concept of an "apparent lattice parameter" clearly indicates strong deviations of the position of Bragg peaks (especially at small angles) from the predicted crystallographic positions. The inference was made that a unique lattice parameter for microcrystallites cannot be determined by standard powder diffractometry. The behavior of nanocrystalline powders under pressure cannot be satisfactorily explained in terms of a unique compressibility coefficient. This also counts in favor of the twophase structure of nanoparticles.Earlier [5][6][7], structurally inhomogeneous zirconia nanoparticles that consist of interpenetrating fragments with different symmetries and are characterized by the orientational relationships "incompatible" from the standpoint of classical crystallography were experimentally found for the first time. Regularly oriented fragments with different symmetries, for which the requirements of classical crystallography are not satisfied (the interface need not be a plane, so that the orientational relationships do not necessarily correspond to the Miller indices and the fragments themselves need not be crystals), were referred to as centaurs [5]. The boundaries of fragments are coherent, and, therefore, these particles can be defined as nanostructures with coherent boundaries.Alok Singh and Tsai [8] revealed that the cubic and icosahedral phases in metal alloys can intergrow in a regular oriented manner. It was found that the threefold axes of the cubic phase coincide in direction with the twofold axes of the icosahedral phase and the cubic twofold axes are almost parallel to the icosahedral fivefold axes. The interface is not a plane, and the orientational relationships do not correspond to rational ratios of the corresponding Miller indices and are inconsistent with the assumption that this cubic phase is a quasicrystalline approximant of the icosahedral phase.The structural inhomogeneity of nanoparticles has become evident owing to widespread use of high-resolution electron microscopy [7,9]. Of special interest are materials prepared by ultrafast solidification, because extreme conditions often lead to the formation of vitreous or unstable crystalline structures and quasicrystals. Specifically, it has been demonstrated that fragments of cubic crystals can intergrow to form a hierarchic st...

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High pressure x-ray diffraction studies on nanocrystalline materials

Cited by 55 publications

References 64 publications

High-pressure crystallography

High-pressure crystallography

Nanoparticle size distribution estimation by a full-pattern powder diffraction analysis

Nanostructures with coherent boundaries and the local approach

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