We present a detailed strain analysis of epitaxial ferroelectric films taking into account multiple sources of strain, including the lattice mismatch between the film and the substrate, thermal strains due to differences in the thermal expansion coefficients of the film and the substrate, and relaxation by the formation of interfacial dislocations. The lattice parameters of the film are calcula...

In order to get a better understanding of wear mechanisms in cutting tool materials, the internal stress states caused by complex external thermo-mechanical loads during cutting processes should be investigated. This can be done using in situ X-ray diffraction with high energy synchrotron radiation. For this reason, in first model tests, the strain state in ceramic cutting tool materials (Al2O3...

X-ray diffraction measurement in the bulk of engineering components allows evaluation of lattice spacing variation by application of Bragg law and hence, by comparison with a strain-free reference specimen, computation of elastic strains and stresses. Diffraction peak position is related to average elastic strain within the scattering grains, whilst diffraction peak shape is related to crystall...

Electron backscatter diffraction (EBSD) has been used to examine the plastic deformation of an ex-service 316 austenitic stainless steel at 297K and 823K at strain rates 3.5x10 -3 s -1 – 4x10 -7 s -1 . The distribution of local misorientations was found to depend on the imposed plastic strain following a lognormal distribution at true strains < 0.1 and a gamma distribution at strains > 0.1. At ...

Core-shell nanowires (NW) have become very prominent systems for band engineered NW heterostructures that effectively suppress detrimental surface states and improve performance of related devices. This concept is particularly attractive for material systems with high intrinsic surface state densities, such as the low-bandgap In-containing group-III arsenides, however selection of inappropriate...

We report on the effect of epitaxial strain magnetic and optical properties perovskite LaCrO3 (LCO) single crystal thin films. Epitaxial LCO films are grown by pulsed laser deposition proper choice substrates to impose different states. A combined experimental theoretical approach is used demonstrate direct correlation between lattice-strain functional properties. The magnetization results show...

To investigate the lattice distortion caused by point defects in As-rich GaAs, we make use of a self-consistent-charge density-functional based tight-binding method. Both relevant defects, the As antisite and the As interstitial, cause significant lattice distortion. In contrast to As interstitials, isolated As antisites lead to lattice strain as well as displacement of nearest neighbor As latt...

Displacement of the specimen surface from the instrument rotation axis in reflection optics diffractometry introduces bias into the measured Bragg peak positions thereby causing systematic shifts in the 2θ-dependent Rietveld parameters. Specimen transparency also results in 2θ-bias, which tends to mimic that from specimen displacement. The authors have investigated the influence of specimen dis...

Simple pair potentials are constructed which give hexagonal-or square-lattice ground states in two dimensions, depending on the value of a single parameter controlling the width of the potential well. Molecular dynamics calculations for free clusters of a few hundred particles are used to examine a structural transition from the square lattice, at low temperatures, to the hexagonal lattice at h...

The deformation of polycrystalline beryllium to strains of 60.8 pct in uniaxial tension and compression was studied by neutron diffraction and modeled using an elasto-plastic self-consistent (EPSC) model. The beryllium response is asymmetric with respect to tension and compression in both the macroscopic behavior, as displayed in the stress/strain curve, and the microscopic lattice response. Th...