A New High-Pressure High-Temperature Phase of Silver Antimonate AgSbO with Strong Ag-O Hybridization.

We report on a new polymorph of silver antimonate AgSbO discovered with the use of high-pressure high-temperature synthesis at 16 GPa and 1380 °C. The crystal structure is determined from X-ray powder diffraction, and we find this new high-pressure phase crystallizes in monoclinic space group 2/ with the following values: = 8.4570(3) Å, = 9.

Impact of Synthesis Method on the Structure and Function of High Entropy Oxides.

The term sample dependence describes the troublesome tendency of nominally equivalent samples to exhibit different physical properties. High entropy oxides (HEOs) are a class of materials where sample dependence has the potential to be particularly profound due to their inherent chemical complexity. In this work, we prepare a spinel HEO of identical nominal composition by five distinct methods, spanning a range of thermodynamic and kinetic conditions: solid state, high pressure, hydrothermal, molten salt, and combustion syntheses.

Enhanced Thermal Stability and Conductivity of FeF Using Ni-Coated Carbon Composites: Application as High-Temperature Cathodes in Thermal Batteries.

Cathode active materials and conductive additives for thermal batteries operating at high temperatures have attracted research interest, with a particular focus on compounds offering high thermal stability. Recently, FeF has been proposed as a candidate for high-voltage cathode materials; however, its commercialization is hindered by its low conductivity. In this study, conductive additives, such as Ni-coated carbon composites (multi-walled carbon nanotubes (MWCNTs) and carbon black (CB)), were utilized to enhance the thermal stability and conductivity of FeF.

Energy-absorption analyses of honeycomb-structured Al-alloy and nylon sheets using modified split Hopkinson pressure bar.

Thin cylindrical honeycomb-structured aluminum alloy and mono-cast (MC) nylon were studied as superior energy-absorbing materials compared to metallic foams. Their energy-absorbing performance was assessed using a modified split Hopkinson pressure bar (SHPB). Key parameters included maximum impact acceleration (a) and its reduction ratio (compared to the none-specimen case).

Crystallization of heavy fermions via epitaxial strain in spinel LiVO thin film.

The mixed-valent spinel LiVO is known as the first oxide heavy-fermion system. There is a general consensus that a subtle interplay of charge, spin, and orbital degrees of freedom of correlated electrons plays a crucial role in the enhancement of quasi-particle mass, but the specific mechanism has remained yet elusive. A charge-ordering (CO) instability of V and V ions that is geometrically frustrated by the V pyrochlore sublattice from forming a long-range CO down to = 0 K has been proposed as a prime candidate for the mechanism.

Development of a low-melting-point eutectic salt and evaluation of its discharge performance for light weight thermal batteries.

This paper proposes low-melting-point eutectic salts containing RbCl as electrolytes for light weight thermal batteries. The handleability of the eutectic salts was remarkably improved for commercialisation. Their performance as thermal battery molten-salt electrolytes was verified using tests on a single cell and a 12-cell stacked battery.

Superconductivity in (Ba,K)SbO.

(Ba,K)BiO constitute an interesting class of superconductors, where the remarkably high superconducting transition temperature T of 30 K arises in proximity to charge density wave order. However, the precise mechanism behind these phases remains unclear. Here, enabled by high-pressure synthesis, we report superconductivity in (Ba,K)SbO with a positive oxygen-metal charge transfer energy in contrast to (Ba,K)BiO.

Universal Bound to the Amplitude of the Vortex Nernst Signal in Superconductors.

A liquid of superconducting vortices generates a transverse thermoelectric response. This Nernst signal has a tail deep in the normal state due to superconducting fluctuations. Here, we present a study of the Nernst effect in two-dimensional heterostructures of Nb-doped strontium titanate (STO) and in amorphous MoGe.

Controlled manipulation of oxygen vacancies using nanoscale flexoelectricity.

Oxygen vacancies, especially their distribution, are directly coupled to the electromagnetic properties of oxides and related emergent functionalities that have implications for device applications. Here using a homoepitaxial strontium titanate thin film, we demonstrate a controlled manipulation of the oxygen vacancy distribution using the mechanical force from a scanning probe microscope tip. By combining Kelvin probe force microscopy imaging and phase-field simulations, we show that oxygen vacancies can move under a stress-gradient-induced depolarisation field.

Temperature dependence of band gap in MoSe grown by molecular beam epitaxy.

We report on a temperature-dependent band gap property of epitaxial MoSe ultrathin films. We prepare uniform MoSe films epitaxially grown on graphenized SiC substrates with controlled thicknesses by molecular beam epitaxy. Spectroscopic ellipsometry measurements upon heating sample in ultra-high vacuum showed temperature-dependent optical spectra between room temperature to 850 °C.

Topotactic Metal-Insulator Transition in Epitaxial SrFeO Thin Films.

Topotactic phase transformation enables structural transition without losing the crystalline symmetry of the parental phase and provides an effective platform for elucidating the redox reaction and oxygen diffusion within transition metal oxides. In addition, it enables tuning of the emergent physical properties of complex oxides, through strong interaction between the lattice and electronic degrees of freedom. In this communication, the electronic structure evolution of SrFeO epitaxial thin films is identified in real-time, during the progress of reversible topotactic phase transformation.

Suppression of Three-Dimensional Charge Density Wave Ordering via Thickness Control.

Barium bismuth oxide (BaBiO_{3}) is the end member of two families of high-T_{c} superconductors, i.e., BaPb_{1-x}Bi_{x}O_{3} and Ba_{1-x}K_{x}BiO_{3}.