Magnetism of pseudospin-1/2 pyrochlore antiferromagnet NaCo(CO)Cl.

Pyrochlore magnets have attracted interest as systems for realizing critical phenomena, rich magnetic structures, associated topological band structures, and nontrivial quantum phases. NaCo(CO)Cl is a pseudospin-1/2 antiferromagnet in which the Coions form a pyrochlore network. Its structural and magnetic properties were investigated using magnetization, heat capacity, ESR, single-crystal x-ray diffraction, powder neutron diffraction and powder inelastic neutron scattering.

SEEMS: A Single Event Effects and Muon Spectroscopy facility at the Spallation Neutron Source.

This study outlines a concept that would leverage the existing proton accelerator at the Spallation Neutron Source (SNS) of Oak Ridge National Laboratory to enable transformative science via one world-class facility serving two missions: Single Event Effects (SEE) and Muon Spectroscopy (μSR). The μSR portion would deliver the world's highest flux and highest resolution pulsed muon beams for material characterization purposes, with precision and capabilities well beyond comparable facilities. The SEE capabilities deliver neutron, proton, and muon beams for aerospace industries that are facing an impending challenge to certify equipment for safe and reliable behavior under bombardment from atmospheric radiation originating from cosmic and solar rays.

Spiral Spin Liquid on a Honeycomb Lattice.

Spiral spin liquids are correlated paramagnetic states with degenerate propagation vectors forming a continuous ring or surface in reciprocal space. On the honeycomb lattice, spiral spin liquids present a novel route to realize emergent fracton excitations, quantum spin liquids, and topological spin textures, yet experimental realizations remain elusive. Here, using neutron scattering, we show that a spiral spin liquid is realized in the van der Waals honeycomb magnet FeCl_{3}.

Manipulation of ionized impurity scattering for achieving high thermoelectric performance in n-type MgSb-based materials.

Achieving higher carrier mobility plays a pivotal role for obtaining potentially high thermoelectric performance. In principle, the carrier mobility is governed by the band structure as well as by the carrier scattering mechanism. Here, we demonstrate that by manipulating the carrier scattering mechanism in n-type MgSb-based materials, a substantial improvement in carrier mobility, and hence the power factor, can be achieved.

Structural, Electronic, and Optical Properties of KSnO with an Offset Hollandite Structure.

We present the compound KSnO, a Sn-containing oxide with a unique structure type among oxides. The compound is orthorhombic and reminiscent of an offset hollandite, where open channels hold a row of four K per channel per cell. UV-visible spectroscopy indicates a wide band gap semiconductor, which is confirmed by first-principles electronic-structure calculations of band structures, densities of states, and optical properties.

Observation of Magnetoelectric Multiferroicity in a Cubic Perovskite System: LaMn(3)Cr(4)O(12).

Magnetoelectric multiferroicity is not expected to occur in a cubic perovskite system because of the high structural symmetry. By versatile measurements in magnetization, dielectric constant, electric polarization, neutron and x-ray diffraction, Raman scattering, as well as theoretical calculations, we reveal that the A-site ordered perovskite LaMn(3)Cr(4)O(12) with cubic symmetry is a novel spin-driven multiferroic system with strong magnetoelectric coupling effects. When a magnetic field is applied in parallel (perpendicular) to an electric field, the ferroelectric polarization can be enhanced (suppressed) significantly.

Field-induced spin-flop in antiferromagnetic semiconductors with commensurate and incommensurate magnetic structures: Li2FeGeS4 (LIGS) and Li2FeSnS4 (LITS).

Li2FeGeS4 (LIGS) and Li2FeSnS4 (LITS), which are among the first magnetic semiconductors with the wurtz-kesterite structure, exhibit antiferromagnetism with TN ≈ 6 and 4 K, respectively. Both compounds undergo a conventional metamagnetic transition that is accompanied by a hysteresis; a reversible spin-flop transition is dominant. On the basis of constant-wavelength neutron powder diffraction data, we propose that LIGS and LITS exhibit collinear magnetic structures that are commensurate and incommensurate with propagation vectors km = [1/2, 1/2, 1/2] and [0, 0, 0.

Unusual relationship between magnetism and superconductivity in FeTe(0.5)Se(0.5).

We use neutron scattering to study magnetic excitations in crystals near the ideal superconducting composition of FeTe(0.5)Se(0.5).