A5091549034- Intermetallics and Advanced Alloy Properties
- Quasicrystal Structures and Properties
- Hydrogen Storage and Materials
- Ferroelectric and Piezoelectric Materials
- Aluminum Alloy Microstructure Properties
- Advancements in Battery Materials
- Semiconductor materials and devices
- Magnetic and transport properties of perovskites and related materials
- Metallic Glasses and Amorphous Alloys
- Solidification and crystal growth phenomena
- Inorganic Chemistry and Materials
- Microwave Dielectric Ceramics Synthesis
- Electron and X-Ray Spectroscopy Techniques
- Ammonia Synthesis and Nitrogen Reduction
- Electronic and Structural Properties of Oxides
- MXene and MAX Phase Materials
- Multiferroics and related materials
- ZnO doping and properties
- X-ray Diffraction in Crystallography
- Advanced Condensed Matter Physics
- Rare-earth and actinide compounds
- Nuclear Materials and Properties
- Titanium Alloys Microstructure and Properties
- Magnetic properties of thin films
- Metallurgical and Alloy Processes
National Institute of Standards and Technology
2012-2022
Theiss Research
2020
Material Measurement Laboratory
2011-2019
National Institute of Standards
2005-2016
DEVCOM Army Research Laboratory
2013
Rutgers, The State University of New Jersey
2002-2004
Bhabha Atomic Research Centre
1997
NTL Institute for Applied Behavioral Science
1996
NIST Center for Neutron Research
1993
Johns Hopkins University
1985-1988
Studies of phase formation in rapidly solidified Al-Mn alloys (composition range 18-22 at.% Mn) show that an icosahedral is replaced by another noncrystallographic phase, a decagonal phase. The example quasicrystal: It has point group ($\frac{10}{m}$ or $\frac{10}{\mathrm{mmm}}$) together with long-range orientational order and one-dimensional translational symmetry. intermediate between crystal both from the symmetry solidification condition points view.
Active learning-the field of machine learning (ML) dedicated to optimal experiment design-has played a part in science as far back the 18th century when Laplace used it guide his discovery celestial mechanics. In this work, we focus closed-loop, active learning-driven autonomous system on another major challenge, advanced materials against exceedingly complex synthesis-processes-structure-property landscape. We demonstrate an methodology for functional inorganic compounds which allow...
Heterogeneous integration of nanomaterials has enabled advanced electronics and photonics applications. However, similar progress been challenging for thermal applications, in part due to shorter wavelengths heat carriers (phonons) compared electrons photons. Here, we demonstrate unusually high isolation across ultrathin heterostructures, achieved by layering atomically thin two-dimensional (2D) materials. We realize artificial stacks monolayer graphene, MoS2, WSe2 with resistance greater...
Chemical and structural heterogeneity the resulting interaction of coexisting phases can lead to extraordinary behaviours in oxides, as observed piezoelectric materials at morphotropic phase boundaries relaxor ferroelectrics. However, such phenomena are rare metallic alloys. Here we show that, by tuning presence textured Co(1-x)Fe(x) thin films, effective magnetostriction λ(eff) large 260 p.p.m. be achieved low-saturation field ~10 mT. Assuming λ(100) is dominant component, this number...
We have fabricated MgxZn1−xO epitaxial composition spreads where the across chip is linearly varied from ZnO to MgO. By using a scanning x-ray microdiffractometer and transmission electron microscopy, we mapped phase evolution spread. discovered unique growth relationship between cubic hexagonal their basal planes are coincident in phase-separated region of diagram 0.37⩽x⩽0.6. The continuously changing band gap spread used as basis for compact broadband photodetector arrays with range...
Band-to-band tunneling field-effect transistors (TFETs) have emerged as promising candidates for low-power integration circuits beyond conventional metal-oxide-semiconductor (MOSFETs) and been demonstrated to overcome the thermionic limit, which results intrinsically in sub-threshold swings of at least 60 mV/dec room temperature. Here, we demonstrate complementary TFETs based on few-layer black phosphorus, multiple top gates create electrostatic doping source drain regions. By electrically...
The coexistence of metallic and semiconducting polymorphs in transition-metal dichalcogenides (TMDCs) can be utilized to solve the large contact resistance issue TMDC-based field effect transistors (FETs). A hexagonal (2H) molybdenum ditelluride (MoTe2) phase, monoclinic (1T') MoTe2 their lateral homojunctions selectively synthesized situ by chemical vapor deposition due small free energy difference between two phases. Here, we have investigated, detail, structural electrical properties...
Epitaxial LiCoO2 (LCO) thin films of different orientations were fabricated by pulsed laser deposition (PLD) in order to model single-crystal behavior during electrochemical reaction. This paper demonstrates that conductive SrRuO3 between a SrTiO3 (STO) substrate and an LCO film allows (1) epitaxial growth with orientation determined STO (2) measurements, such as cyclic voltammetry impedance spectroscopy. Scanning transmission electron microscopy (S/TEM SEM) has demonstrated relationship...
Structural phase transitions serve as the basis for many functional applications including shape memory alloys (SMAs), switches based on metal-insulator (MITs), etc. In such materials, lattice incompatibility between phases often results in a thermal hysteresis, which is intimately tied to degradation of reversibility transformation. The non-linear theory martensite suggests that hysteresis martensitic transformation solely determined by constants, and conditions proposed geometrical...
Nuclear \ensuremath{\gamma}-ray resonance (M\"ossbauer effect) results are presented from rapidly solidified Al-(Mn,Fe) alloys which contain the orientationally ordered phase with icosahedral point-group symmetry. Detailed analysis of spectra obtained is consistent an quasicrystalline model for structure this phase.
We synthesized composites consisting of silicon nanowires (SiNWs) coated with magnesium (Mg) and silicide (Mg2Si) for lithium-ion battery anodes studied their electrochemical cycling stability degradation mechanisms. Compared to bare SiNWs, both Mg- Mg2Si-coated materials show significant improvement in coulombic efficiency during cycling, pure Mg coating being slightly superior by ∼1% each cycle. XPS measurements on cycled nanowire forests gave quantitative information the composition SEI...
This study details a “wet” atomic layer deposition process that uses potential modulation and H adsorption to terminate Ir at high overpotentials. The ultrathin films match or exceed the best reported electrocatalytic activity for oxygen evolution reaction (OER) hydrogen production oxidation (HER HOR) on bulk electrodes.
The goal of the Robust Affordable Next Generation Energy Storage System (RANGE)-BASF program is to provide an alternative solution for energy storage media that powers electric vehicles other than existing Li-ion battery. With use a rare-earth-free metal hydride (MH) as active negative electrode material, together with core-shell type alpha-beta nickel hydroxide positive and sealed pouch design, density 145 Wh·kg−1 cost model $120 kWh−1 are shown be feasible. Combined proven safety record...