Learn More
Electron diffraction via the transmission electron microscope is a powerful method for characterizing the structure of materials, including perfect crystals and defect structures. The advantages of electron diffraction over other methods, e.g., x-ray or neutron, arise from the extremely short wavelength (≈2 pm), the strong atomic scattering, and the ability(More)
The goal of the Robust Affordable Next Generation Energy Storage System (RANGE)-BASF program is to provide an alternative solution for the energy storage media that powers electric vehicles other than the existing Li-ion battery. With the use of a rare-earth-free metal hydride (MH) as the active negative electrode material, together with a core-shell type(More)
The grain boundaries of three Laves phase-related body-center-cubic (bcc) solid-solution, metal hydride (MH) alloys with different phase abundances were closely examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and more importantly, electron backscatter diffraction (EBSD) techniques. By using EBSD, we were able to(More)
Epitaxial ferroelectric films undergoing a cubic-tetragonal phase transformation relax internal stresses due to the structural phase transformation and the difference in the thermal expansion coefficients of the film and the substrate by forming polydomain structures. The most commonly observed polydomain structure is the c/a/c/a polytwin which only(More)
We have fabricated a series of composition spreads consisting of ferroelectric BaTiO 3 and piezomagnetic CoFe 2 O 4 layers of varying thicknesses modulated at nanometer level in order to explore artificial magnetoelectric thin-film heterostructures. Scanning microwave microscopy and scanning superconducting quantum interference device microscopy were used(More)
PbZr 0.2 Ti 0.8 O 3 ͑PZT͒ thin films with and without La 0.5 Sr 0.5 CoO 3 ͑LSCO͒ electrodes were grown epitaxially on ͑001͒ SrTiO 3 at 650 °C by pulsed laser deposition. The domain structure of the 400 nm thick PZT films with different electrode layer configurations was investigated by x-ray diffraction and transmission electron microscopy. The c-domain(More)
A new methodology for determining the radial elastic modulus of a one-dimensional nanostructure laid on a substrate has been developed. The methodology consists of the combination of contact resonance atomic force microscopy (AFM) with finite element analysis, and we illustrate it for the case of faceted AlN nanotubes with triangular cross-sections. By(More)
We have fabricated Mg x Zn 1Ϫx O epitaxial composition spreads where the composition across the chip is linearly varied from ZnO to MgO. By using a scanning x-ray microdiffractometer and transmission electron microscopy, we have mapped the phase evolution across the spread. We have discovered a unique growth relationship between cubic and hexagonal Mg x Zn(More)
This work attempts to optimize past research results on lead zirconate titanate (PZT) using the fabrication processes at the U.S. Army Research Laboratory so as to achieve a high degree of {001} texture and improved piezoelectric properties. A comparative study was performed between Ti/Pt and TiO 2 /Pt bottom electrodes. The results indicate that the use of(More)
Chemical and structural heterogeneity and the resulting interaction of coexisting phases can lead to extraordinary behaviours in oxides, as observed in piezoelectric materials at morphotropic phase boundaries and relaxor ferroelectrics. However, such phenomena are rare in metallic alloys. Here we show that, by tuning the presence of structural heterogeneity(More)