Epitaxially grown La0.7Sr0.3MnO3 thin films show resistance modulations induced by the inverse piezoeffect of the employed Pb(Mg1∕3Nb2∕3)O3-PbTiO3(001) (PMN-PT) substrates. The in-plane strain state of the films can continuously be tuned by application of a piezovoltage to PMN-PT. The lattice deformation of a PMN-PT(001) substrate was quantified by x-ray measurements under an electric field. Variation of in-plane lattice parameters by ∼0.06% reversibly changes the resistance of the manganite films by up to 9% at 300 K and shifts the magnetic Curie temperature. Films of different thicknesses from 50 to 290 nm, offering different as-grown strain states, have been studied.

The steel of Damascus blades, which were first encountered by the Crusaders when fighting against Muslims, had features not found in European steels--a characteristic wavy banding pattern known as damask, extraordinary mechanical properties, and an exceptionally sharp cutting edge. Here we use high-resolution transmission electron microscopy to examine a sample of Damascus sabre steel from the seventeenth century and find that it contains carbon nanotubes as well as cementite nanowires. This microstructure may offer insight into the beautiful banding pattern of the ultrahigh-carbon steel created from an ancient recipe that was lost long ago.

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Recent years have seen an increasing research effort focused on nanoscaling of metal borides, a class of compounds characterized by a variety of crystal structures and bonding interactions. Despite being subject to an increasing number of studies in the application field, comprehensive studies of the size-dependent structural changes of metal borides are limited. In this work, size-dependent microstructural analysis of the VB 2 nanocrystals prepared by means of a size-controlled colloidal solution synthesis is carried out using X-ray powder diffraction. The contributions of crystallite size and strain to X-ray line broadening is separated by introducing a modified Williamson−Hall method taking into account different reflection profile shapes. For average crystallite sizes smaller than ca. 20 nm, a remarkable increase of lattice strain is observed together with a significant contraction of the hexagonal lattice decreasing primarily the cell parameter c. Exemplary density-functional theory calculations support this trend. The size-dependent lattice contraction of VB 2 nanoparticles is associated with the decrease of the interatomic boron distances along the c-axis. The larger fraction of constituent atoms at the surface is formed by boron atoms. Accordingly, lattice contraction is considered to be a surface effect. The anisotropy of the sizedependent lattice contraction in VB 2 nanocrystals is in line with the higher compressibility of its macroscopic bulk structure along the c-axis revealed by theoretical calculations of the respective elastic properties. Transmission electron microscopy indicates that the VB 2 nanocrystals are embedded in an amorphous matrix. X-ray photoelectron spectroscopy analysis reveals that this matrix is mainly composed of boric acid, boron oxides, and vanadium oxides. VB 2 nanocrystals coated with these oxygen containing amorphous species are stable up to 789°C as evidenced by thermal analysis and temperature dependent X-ray diffraction measurements carried out under Ar atmosphere. Electrokinetic measurement indicates that the aqueous suspension of VB 2 nanoparticles with hydroxyl groups on the surface region has a good stability at neutral and basic pH arising from electrostatic stabilization