Publications

Aug, 2026

Journal

Hierarchical microstructure of Yb-filled skutterudites through ultrasonically atomized spherical powders for enhanced thermoelectric performance

Hierarchical microstructures are widely explored as a strategy to reduce lattice thermal conductivity in thermoelectric materials while preserving favorable electronic transport. Here we demonstrate that ultrasonic atomization of precursor powders provides an intrinsic pathway to generate such architectures in n-type Yb0.3Co4Sb12 skutterudites. Materials were synthesized b…

May, 2026

Journal

Regulating in situ gaseous deposition to construct highly durable Fe–N–C oxygen-reduction fuel cell catalysts

The activity–stability trade-off challenges the design of high-performance atomically dispersed iron–nitrogen–carbon (Fe–N–C) catalysts for the acidic oxygen reduction reaction in polymer electrolyte fuel cells. Here we develop an in situ chemical vapour deposition approach during catalyst synthesis to break the trade-off, producing highly stable Fe–N–C catalysts while mai…

Apr, 2026

Journal

The Effects of Iron and Manganese Doping on the Carbonation of Brucite [Mg(OH)2]

Brucite [Mg(OH)2] is a promising sorbent for carbon dioxide removal (CDR) due to its availability and low calcination temperatures. However, natural and synthetic brucites tend to contain metal impurities, such as iron or manganese, and how these impurities affect the interfacial chemical reactivity is uncertain. Here, the impact of low concentrations of iron and manganese…

Feb, 2026

Journal

Leveraging Polymorphism in YbCuBi to Map Transport and Elastic Properties

AMX Zintl compounds with the hexagonal ZrBeSi structure have gained significant attention for their remarkable vacancy tolerance and low thermal conductivity. Their 2D honeycomb sublattice, composed of M–X covalent bonds, is believed to contribute to high anharmonicity and unusual thermal transport properties. In this study, we explore the temperature-dependent polymorphis…

Jan, 2026

Journal

Electric Field Control of Phonon Lifetimes and Thermal Conductivity in Relaxor-Based Ferroelectric

The demand for high energy efficiency drives intense interest in thermal-management technology. Phonons are a major contributor to heat transfer in solids and controlling them through external stimuli is a key challenge for thermal management due to their weak interactions with applied fields. We report significant changes in phonon transport with the application of an ele…

Nov, 2025

Journal

Kohn Anomalies and Phonon Anharmonicity in Iridium

Elemental iridium presents surprising challenges for both inelastic neutron scattering (INS) and theoretical thermal transport calculations due to its high neutron absorption cross-section and strong electron-phonon interactions, respectively. Here, we overcome these challenges to measure temperature-dependent phonon dispersion curves, compare these with calculations based…

Oct, 2025

ORNL Report

Materials Signatures of Metallic Phases: Final Report

Oct, 2025

Journal

Expanding the homogeneity range of UFe2: Formation of Laves phase UFe2+Ni

Uranium-based intermetallic Laves phases (UM$_2$) provide valuable insight into the interplay of 5f electron hybridization and magnetic properties. However, ferromagnetism in these compounds is rare. UFe$_2$ is a cubic C15 Laves phase with largest Curie temperature ($T_C$) of all such compounds, at 162 K. In this study, we report the synthesis and characterization of a nov…

Sep, 2025

Journal

Constraints on magnetism and correlations in RuO2 from lattice dynamics and Mössbauer spectroscopy

We provide experimental evidence for the absence of a magnetic moment in bulk RuO2, a candidate altermagnetic material, by using a combination of Mössbauer spectroscopy, nuclear forward scattering, inelastic X-ray and neutron scattering, and density functional theory calculations. Using complementary Mössbauer and nuclear forward scattering, we determine the Ru magnetic hy…

Sep, 2025

Journal

New precious metal containing normal spinels: LiRhRu1-xIrxO4, LiFeIr1-xRuxO4, and LiCoIr1-xRuxO4

Large spin-orbit-coupled cations in geometrically frustrated crystal structures have the most suitable setting for exploring novel exotic states of matter. Spinel oxides (AM2O4) are well-known examples of geometrically frustrated systems. In this study, we report for the first time the synthesis of compositions LiRhRu1-xIrxO4 (x = 0–0.5), LiFeIr1-xRuxO4 (x = 0–0.5), and Li…

Aug, 2025

Journal

Synergy between Ni and Fe in NiFe aerogel oxygen evolution reaction catalyst: in situ57Fe Mössbauer and X-ray absorption spectroscopy studies

Anion-exchange-membrane water electrolyzers (AEMWE) for hydrogen production have attracted interest because cost-effective Ni- and Fe-based catalysts can be used for the oxygen evolution reaction (OER). Although NiFe oxide/hydroxide-based catalysts have been extensively studied, the role of Fe and its chemical state during OER are not well understood, with inconsistent fin…

Aug, 2025

Journal

A Mössbauer Spectroscopy Investigation of Nickel-Zinc Ferrites Synthesized by a Self-Combustion Method for Soft Magnetic Core Applications

Soft ferrites are materials of interest for magnetic cores, as used for wireless charging transformers. Their low permeabilities, high resistivity, and magnetic polarization make them interesting for high-power electric vehicle charging and drive systems. The nickel-zinc-doped ferrites are of particular interest; however, the compositional space is quite large with respect…