Revealing phase boundaries by weighted parametric structural refinement

2019 ◽  
Vol 26 (5) ◽  
pp. 1638-1643
Author(s):  
Frederick Marlton ◽  
Stefano Checchia ◽  
John Daniels
Keyword(s):  
Parametric Method ◽  
Structural Phase ◽  
Lead Free ◽  
Powder Diffraction Data ◽  
Structural Phase Transitions ◽  
Structural Refinement ◽  
Peak Splitting ◽  
Phase Boundary Composition ◽  
Weak Peak

Parametric Rietveld refinement from powder diffraction data has been utilized in a variety of situations to understand structural phase transitions of materials in situ. However, when analysing data from lower-resolution two-dimensional detectors or from samples with overlapping Bragg peaks, such transitions become difficult to observe. In this study, a weighted parametric method is demonstrated whereby the scale factor is restrained via an inverse tan function, making the phase boundary composition a refinable parameter. This is demonstrated using compositionally graded samples within the lead-free piezoelectric (BiFeO3) x (Bi0.5K0.5TiO3) y (Bi0.5Na0.5TiO3)1–x–y and (Bi0.5Na0.5TiO3) x (BaTiO3)1–x systems. This has proven to be an effective method for diffraction experiments with relatively low resolution, weak peak splitting or compositionally complex multiphase samples.

A furnace for in situ synchrotron Laue diffraction and its application to studies of solid-state phase transformations

1990 ◽  
Vol 23 (6) ◽  
pp. 545-549 ◽  
Author(s):  
H. L. Bhat ◽  
S. M. Clark ◽  
A. El Korashy ◽  
K. J. Roberts
Keyword(s):  
Experimental Data ◽  
Thermal Stability ◽  
Phase Transitions ◽  
Solid State ◽  
Synchrotron Radiation ◽  
Structural Phase ◽  
Structural Phase Transitions ◽  
Laue Diffraction ◽  
Thermal Stability Of

The design of a new microfurnace for use for Laue diffraction studies of solid-state transformations is described. The furnace operates in the temperature range 298–573 K with a thermal stability of about ± 0.1 K. The potential of the synchrotron-radiation Laue diffraction technique for studies of structural phase transitions is demonstrated. Experimental data on phase transitions in caesium periodate, potassium tetrachlorozincate and pentaerythritol are presented.

(C3N2H5)3Sb2I9 and (C3N2H5)3Bi2I9 : Ferroelastic Lead-Free Hybrid Perovskite-Like Materials as the Potential Semiconducting Absorbers

2022 ◽  
Author(s):  
Przemyslaw Szklarz ◽  
Ryszard Jakubas ◽  
Wojciech Medycki ◽  
Anna Gągor ◽  
Jakub Cichos ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Structural Phase ◽  
Lead Free ◽  
Structural Phase Transitions ◽  
Inorganic Hybrid ◽  
Hybrid Perovskite ◽  
Hybrid Crystals

We have synthesised and characterised novel organic-inorganic hybrid crystals: (C3N2H5)3Sb2I9 and (C3N2H5)3Bi2I9 (PSI and PBI). The thermal DSC, and TG analyses indicate four structural phase transitions (PTs) at 366.8/366.2, 274.6/275.4,...

Raman Microscopy Investigations and Electrical Characterisation of Indentation-Induced Phase Transformations in Silicon

2005 ◽  
Vol 480-481 ◽  
pp. 225-230 ◽  
Author(s):  
Maha M. Khayyat ◽  
David G. Hasko ◽  
M. Munawar Chaudhri
Keyword(s):  
Phase Transitions ◽  
Room Temperature ◽  
Structural Phase ◽  
Transition Process ◽  
Metallic Phase ◽  
Raman Microscopy ◽  
Structural Phase Transitions ◽  
Electrical Measurements ◽  
Phase Transition Process

Indentation-induced structural phase transitions in single crystal Si(100) and amorphous silicon a-Si have been investigated for indentations made at room temperature and at 77 K. The experimental techniques employed were (1) Raman microscopy and (2) in situ electrical resistance measurement of the indentation region of the plastically deformed silicon. The Raman spectra from residual indentations revealed that although phase transitions did occur when indentations were made at room temperature, there were no phase transitions when indentations were made at 77 K. This difference in behaviour has been explained on the rise of temperature during the room temperature indentations, which may assist the phase transition process. The in situ electrical measurements have revealed that the deformed Si(100) yielded Ohmic behaviour, consistent with the view that during the indentation the cubic silicon transforms to the beta-Sn metallic phase (i.e. body-centre tetragonal).

Pressure-induced phase transition in hydrogen-bonded molecular crystal acetamide: combined Raman scattering and X-ray diffraction study

RSC Advances ◽  
2015 ◽  
Vol 5 (103) ◽  
pp. 84703-84710 ◽  
Author(s):  
Lei Kang ◽  
Kai Wang ◽  
Shourui Li ◽  
Xiaodong Li ◽  
Bo Zou
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Raman Scattering ◽  
Diffraction Study ◽  
Molecular Crystal ◽  
Structural Phase ◽  
Structural Phase Transitions ◽  
X Ray Diffraction ◽  
X Ray

Two structural phase transitions are observed at ∼0.9 and ∼3.2 GPa in acetamide using in situ synchrotron X-ray diffraction (XRD) and Raman scattering techniques.

Intermetallic Phases in Ti-Ag-Zr-Ni Alloys

2000 ◽  
Vol 644 ◽  
Author(s):  
Radu C. Nicula ◽  
Adrian D. Jianu ◽  
Mihaela C. Bunescu ◽  
Ulrich E. Ponkratz ◽  
Manuela E. Stir ◽  
...  
Keyword(s):  
Structural Phase ◽  
Processing Parameters ◽  
Structural Phase Transitions ◽  
Scanning Calorimetry ◽  
Ni Alloys ◽  
Synchrotron Radiation Diffraction ◽  
Synthesis And Processing ◽  
Bulk Nanocrystalline ◽  
Nanocrystalline Phases

AbstractTitanium and zirconium based metallic glasses and crystalline intermetallic compounds with improved mechanical properties are presently a field of intense application-oriented research. The formation and stability of nanocrystalline phases in Ag-substituted Ti-Zr-Ni alloys was followed using in-situ high-temperature synchrotron radiation diffraction experiments. The substitution of Ti with Ag enhances the formation of amorphous or nanostructured phases during rapid solidification. High-resolution powder diffraction and electron microscopy investigations indicate that the as-quenched alloys are either amorphous or in a mixed nanostructured state. Upon heating, the alloy structure transforms to a fine mixture of icosahedral and crystalline phases depending on the alloy composition and thermal processing parameters. Differential scanning calorimetry studies were performed in order to identify the nature and sequence of the observed structural phase transitions. The experimental results are discussed with respect to the non- equilibrium synthesis and processing of bulk amorphous and bulk nanocrystalline materials in Ti/Zr-based alloys.

High-energy X-ray applications: current status and new opportunities

2017 ◽  
Vol 32 (S2) ◽  
pp. S22-S27 ◽  
Author(s):  
Dubravka Šišak Jung ◽  
Tilman Donath ◽  
Oxana Magdysyuk ◽  
Jozef Bednarcik
Keyword(s):  
Structural Information ◽  
Structural Phase ◽  
High Energy ◽  
Current Status ◽  
X Rays ◽  
Structural Phase Transitions ◽  
X Ray ◽  
Cdte Detector

Characterization of semi and noncrystalline materials, monitoring structural phase transitions in situ, and obtaining structural information together with spatial distribution of the investigated material are only a few applications that hugely benefitted from the combination of high-energy X-rays and modern algorithms for data processing. This work examines the possibility of advancing these applications by shortening the data acquisition and improving the data quality by using the new high-energy PILATUS3 CdTe detector.

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