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Lu, Ping

Publications and source records attributed to Lu, Ping.

At least 325 records · Page 18
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DOE OSTI2014

Novel Electroforming-Free Nanoscaffold Memristor with Very High Uniformity, Tunability, and Density

Dynamical tuning of the concentration of defects in oxides provides a route to controlling new functionalities. [ 1 ] The chemical potential to capture the functionalities driven by mobile ions and defects can be one of the key control parameters (as well as electric field, magnetic field, and stress) for tuning the functionality of complex oxides. [ 1 ] Interesting signatures related to oxygen vacancies have been explicitly observed in widespread physical applications, including solid oxide fuel cells, [ 2 ] catalysts, [ 3 ] optoelectronics, [ 4 ] and electronics. [ 5–14 ]

36 MATERIALS SCIENCE↗
DOE OSTI2014

Atomic-Scale Chemical Imaging and Quantification of Metallic Alloy Structures by Energy-Dispersive X-Ray Spectroscopy

Determination of atomic-scale crystal structure for nanostructured intermetallic alloys, such as magnetic alloys containing Al, Ni, Co (alnico) and Fe, is crucial for understanding physical properties such as magnetism, but technically challenging due to the small interatomic distances and the similar atomic numbers. By applying energy-dispersive X-ray spectroscopy (EDS) mapping to the study of two intermetallic phases of an alnico alloy resulting from spinodal decomposition, we have determined atomic-scale chemical composition at individual lattice sites for the two phases: one is the B2 phase with Fe0.76Co0.24 -Fe0.40Co0.60 ordering and the other is the L21 phase with Ni0.48Co0.52 at A-sites, Al at BΙ-sites and Fe0.20Ti0.80 at BΙΙ-sites, respectively. The technique developed through this study represents a powerful real-space approach to investigate structure chemically at the atomic scale for a wide range of materials systems.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Equilibrium Cu-Ag nanoalloy structure formation revealed by in situ scanning transmission electron microscopy heating experiments

Using in situ scanning transmission electron microscopy heating experiments, we observed the formation of a 3-dimensional (3D) epitaxial Cu-core and Ag-shell equilibrium structure of a Cu-Ag nanoalloy. The structure was formed during the thermal interaction of Cu(∼12 nm) and Ag NPs(∼6 nm) at elevated temperatures (150–300 °C) by the Ag NPs initially wetting the Cu NP along its (111) surfaces at one or multiple locations forming epitaxial Ag/Cu (111) interfaces, followed by Ag atoms diffusing along the Cu surface. This phenomenon was confirmed through Monte Carlo simulations to be a nanoscale effect related to the large surface-to-volume ratio of the NPs.

36 MATERIALS SCIENCE↗