The aim of the present study was to create a nanofibrous membrane functionalized with a combination of Cu and Zn nanoclusters, and to evaluate its virucidal effects against both the influenza A virus (IAV) and SARS-CoV-2, as we previously demonstrated that nanofibrous materials modified with Cu nanoclusters can passivate SARS-CoV-2 virions. In contrast, Zn nanoclusters have a more potent virucidal activity against IAV virions. Poly(vinylidene fluoride) (PVDF) membranes activated with Cu and Zn nanoclusters were successfully fabricated by electrospinning a PVDF solution in dimethylacetamide (DMA) with the addition of 2.0 wt% Cu(NO₃)₂·2.5H₂O and 2.0 wt% ZnCl₂. Characterization of modified materials was performed using scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, mercury intrusion porosimetry, thermogravimetric analysis, contact angle measurement, and microwave plasma atomic emission spectroscopy. In addition, filtration efficiency was determined using particles with diameters ranging from 100 nm to 3000 nm. Tissue culture infectious dose 50 assay (TCID₅₀) was employed to determine virucidal activity against IAV (H1N1) and SARS-CoV-2 (Wuhan-Hu-1). A nanofibrous material containing both Cu and Zn nanoclusters with a thickness of ∼200 μm showed ≥ 99% filtration efficiency. Both Cu and Cu/Zn containing materials exhibited similar antiviral activity against SARS-CoV-2 virions; however, the material activated with Cu and Zn induced a more rapid decline in viral titers. The composite material showed very high virucidal activity against IAV.

We investigate the pressure-dependent magnetism of the quasi-one-dimensional solid solution Ca1-xNaxCr2O4 using neutron diffraction, Cr K-edge x-ray absorption spectroscopy, and muon spin rotation/relaxation. Na substitution is known to increase oxygen-ligand hole density (partial Cr3+ to Cr4+ character) and to drive the evolution from incommensurate order in CaCr2O4 to commensurate antiferromagnetism in NaCr2O4, suggesting a complex interplay between charge doping and structural changes. Here we apply hydrostatic pressure to tune the lattice without altering the nominal hole count, thereby separating compression effects from ligand-hole physics. For x = 0 and x = 0.5 the magnetic transition temperature is essentially pressure independent within our explored range, whereas in NaCr2O4 long-range order is progressively suppressed with pressure, as seen by a decrease of TN and of the magnetic Bragg intensity. Over the same pressure range, Cr K-edge x-ray absorption spectroscopy shows no resolvable change in the average Cr valence or coordination, and the refined corner-sharing Cr–O–Cr geometry remains nearly invariant within uncertainty. Extrapolating the pressure dependence of the magnetic order parameter suggests a critical pressure Pc = 107(8) kbar for complete suppression of long-range order. These results support ligand-hole density as the primary control parameter across Ca1-xNaxCr2O4, with pressure acting as a secondary electronic tuning knob that weakens ordering in the Na-rich end member without inducing a new magnetic phase.

Superconductivity in TiSe2 emerges when the charge density wave (CDW) order is suppressed under pressure or doping. Recent theoretical and experimental studies suggest that a Lifshitz transition plays a key role in stabilizing the superconducting phase. Here, we present muon spin resonance measurements of pressurized TiSe2, revealing a two-gap superconducting state. Our results indicate that the smaller gap contributes unexpectedly strongly to the total superfluid density. This effect is consistent with an enhanced density of states in a newly formed Fermi surface pocket at the Lifshitz transition. These findings provide microscopic insight into the interplay between CDW suppression, Fermi surface reconstruction, and multi-gap superconductivity in TiSe2, demonstrating how pressure-induced changes in electronic structure can shape superconducting properties in layered materials.

In quantum magnetic materials it is common to observe both static and dynamic lattice effects on the magnetic excitation spectrum. Less common is to find that the magnetic correlations have a significant impact on the phonon spectrum. Here we study the metal-organic material (C5H9NH3)2CuBr4(Cu-CPA), in which an explanation of the low-lying excitations depends crucially on a full understanding of both the spin and lattice subsystems. We report high-resolution neutron spectroscopy enabled by large, deuterated single crystals that reveal how both sectors are affected by the recently discovered structural phase transition. By measuring over several Brillouin zones, we disentangle the vibrational contribution to the spectrum in order to obtain an accurate estimate of the quasi-one-dimensional magnetic signal. The low-energy magnetic excitations are dominated by two gaps, Ab = 0.41 meV and Aa = 0.55 meV, which contribute with equal intensity ratios, confirming that Cu-CPA realizes a two-ladder spin Hamiltonian, and we deduce the magnetic interaction parameters of both ladders. The phonon spectrum contains highly localized modes at an anomalously low energy around 2 meV. For half of these modes, this characteristic frequency drops by approximately 5% as magnetic correlations become established with decreasing temperature, and we connect this apparent "elastomagnetic" behavior with the location and structure of the cyclopentylammonium rings.

Interfacial structures on the nanoscale are crucial for a wide field of applications ranging from biological membranes in life sciences through organic solar cells and industrial coatings in soft matter to hard matter structures. The latter include thin film coatings and materials such as magnetic nanoparticles and topological structures like magnetic skyrmions. Advancing such application rests on the ability to reveal structures at hidden interfaces at different length scales. Techniques like scanning probe microscopy provide information about surface structures and topology with high precision, but are limited to the probe interacting with the surface. The high penetration power of neutrons, their sensitivity to light elements and the capability to probe magnetic structures makes grazing incidence small-angle neutron scattering (GISANS) a valuable, but yet underexploited, tool for organic materials and condensed matter systems and, in particular, to study buried interfaces. Together with specular and off specular neutron reflectometry, interfacial structures on length scales from a few nanometres up to micrometres can be revealed. Apart from giving a comprehensive introduction to the GISANS technique, we will highlight the importance of interfacial layer structures in different fields and how recent developments in the surface techniques have revealed common features in a range of systems. This includes the formation, structure, and topology of the interfaces of and between materials, which are controlled by the same fundamental molecular and colloidal forces.

To achieve long-lasting, high-performance lithium-ion batteries, local inhomogeneity in current density must be avoided. One driver of such inhomogeneity is the spinodal decomposition of active materials into Li-rich and Li-poor phases during charge and discharge, respectively. Whether or not such phase separation occurs is linked to the dynamics of lithium (Li) at the active material surface and within its bulk. Here, we show that particle surface coatings can be designed to inhibit phase separation. Using LiFePO4 as a model system, we prepare particles with different coatings in order to tune Li dynamics and electronic structure and thereby induce or prevent phase separation, which we verify through experiment and ab initio calculations. We then leverage our findings to create a mixed ceramic-carbon coating that mitigates phase separation down to rates as low as 0.1C and simultaneously enables fast (dis)charge up to 5C.

A major challenge in condensed matter physics is integrating topological phenomena with correlated electron physics to leverage both types of states for next-generation quantum devices. Metal-insulator transitions are central to bridging these two domains while simultaneously serving as on-off switches for electronic states. Here, we demonstrate how the prototypical material of K2Cr8O16 undergoes a ferromagnetic metal-insulator transition accompanied by a change in band topology. Through inelastic x-ray and neutron scattering experiments combined with first-principles theoretical calculations, we show that this transition is not driven by a Peierls mechanism, given the lack of phonon softening. Instead, we establish the transition as a topological metal-insulator transition within the ferromagnetic phase with potential axionic properties, where electron correlations play a key role in stabilizing the insulating state. These results reveal how a metal-insulator transition provides a pathway through which magnetism, topology, and electronic correlations interact. 

Demand for fast-charging lithium-ion batteries (LIBs) has escalated incredibly in the past few years. A conventional method to improve the performance is to chemically partly substitute the transition metal with another to increase its conductivity. In this study, we have chosen to investigate the lithium diffusion in doped anatase (TiO₂) anodes for high-rate LIBs. Substitutional doping of TiO₂ with the pentavalent Nb has previously been shown to increase the high-rate performances of this anode material dramatically. Despite the conventional belief, we explicitly show that Nb is mobile and diffusing at room temperature, and different diffusion mechanisms are discussed. Diffusing Nb in TiO₂ has staggering implications concerning most chemically substituted LIBs and their performance. While the only mobile ion is typically asserted to be Li, this study clearly shows that the transition metals are also diffusing, together with the Li. This implies that a method that can hinder the diffusion of transition metals will increase the performance of our current LIBs even further.

Layered transition metal dichalcogenides (TMDs) are model systems to investigate the interplay between superconductivity and the charge density wave (CDW) order. Here, we use muon spin rotation and relaxation (mu+SR) to probe the superconducting ground state of polycrystalline 2H-TaS2, which hosts a CDW transition at 76 K and superconductivity below 1 K. The mu+SR measurements, conducted down to 0.27 K, are consistent with a nodeless, BCS-like single-gap s-wave state. Fits to the temperature dependence of the depolarization rate and Knight shift measurements support spin-singlet pairing. Crucially, no evidence of time-reversal symmetry breaking (TRSB) is observed, distinguishing 2H-TaS2 from polymorphs like 4Hb-TaS2, where TRSB and unconventional superconductivity have been reported. These findings establish 2H-TaS2 as a canonical BCS superconductor and provide a reference point for understanding the diverse electronic ground states that emerge in structurally distinct TMD polymorphs.

This study explores the magnetic properties of YbCo₂ through specific heat measurements, muon spin rotation spectroscopy, and neutron diffraction under external magnetic fields. A magnetic transition anomaly at 0.3 K in specific heat marks the onset of magnetic order, further corroborated by muon spin resonance data. A second anomaly in specific heat observed in an applied magnetic field indicates a field-induced change of magnetic ordering, confirmed by neutron diffraction experiment in magnetic fields. Yb magnetic moments exhibit a collinear ferromagnetic ordering, while Co moments align antiparallel to Yb moments at low magnetic fields. Increasing the external magnetic field, Co moments develop an additional antiferromagnetic component, modifying the overall magnetic structure. The observed magnetic order in low and high magnetic fields is consistently described by the single magnetic space group Imm'a’ and aligns well with theoretical predictions.