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Phonons in condensed matter materials transmit energy through atomic lattices as coherent vibrational waves. Like electronic and photonic properties, an improved understanding of phononic properties is essential for the development of functional materials, including thermoelectric materials. Recently, an Einstein rattling mode was found in thermoelectric material Na0.8CoO2, due to the large displacement of Na between the [CoO₂] layers.

Unlike conventional magnets where the magnetic moments are partially or completely static in the ground state, in a quantum spin liquid they remain in collective motion down to the lowest temperatures. The importance of this state is that it is coherent and highly entangled without breaking local symmetries.

New exotic phenomena have recently been discovered in oxides of paramagnetic Ir⁴⁺ ions, widely known as ‘iridates’. Their remarkable properties originate from concerted effects of the crystal field, magnetic interactions and strong spin-orbit coupling, characteristic of 5d metal ions.

Researchers working with Wojciech Hajdas at the Paul Scherrer Institute PSI have developed a detector called POLAR. This instrument is expected to search out and investigate so-called gamma ray bursts coming from the depths of the universe. Gamma ray bursts are eruptions of high-energy light that despite being extremely strong remain, up to now, only poorly understood.

The temperature-pressure phase diagram of the ferromagnet LaCrGe₃ is determined for the first time from a combination of magnetization, muon-spin-rotation, and electrical resistivity measurements. The ferromagnetic phase is suppressed near 2.1 GPa, but quantum criticality is avoided by the appearance of a magnetic phase, likely modulated, AFM_Q.

The MEG experiment makes use of one of the world’s most intense low energy muon beams, in order to search for the lepton flavour violating process μ+→e+γ . We determined the residual beam polarization at the thin stopping target, by measuring the asymmetry of the angular distribution of Michel decay positrons as a function of energy. The initial muon beam polarization at the production is predicted to be Pμ=−1Pμ=−1 by the Standard Model (SM) with massless neutrinos.

We investigate the band structure of BaBiO₃, an insulating parent compound of doped high-T_c superconductors, using in situ angle-resolved photoemission spectroscopy on thin films. The data compare favorably overall with density functional theory calculations within the local density approximation, demonstrating that electron correlations are weak. The bands exhibit Brillouin zone folding consistent with known BiO₆ breathing distortions.

We report ac susceptibility, specific heat, and neutron scattering measurements on a dipolar-coupled antiferromagnet LiYbF₄. For the thermal transition, the order-parameter critical exponent is found to be 0.20(1) and the specific-heat critical exponent −0.25(1). The exponents agree with the 2D XY/h₄ universality class despite the lack of apparent two-dimensionality in the structure.

The organization of single-molecule magnets (SMMs) on surfaces via thermal sublimation is a prerequisite for the development of future devices for spintronics exploiting the richness of properties offered by these magnetic molecules. However, a change in the SMM properties due to the interaction with specific surfaces is usually observed.

Understanding when a material crystallizes is of fundamental importance in condensed matter. In many materials, the presence of point defects suppresses crystallization. Surprisingly, colloidal hydrogels can overcome this limitation: A small number of large microgels can spontaneously deswell to fit in the crystal lattice of smaller microgels, thus avoiding the occurrence of point defects.

During the anisotropic growth from globular to wormlike micelles, the basic interactions among distinct parts of the surfactant monomer, its counterion, and additives are fundamental to tune molecular self-assembly. We investigate the addition of sodium salicylate (NaSal) to hexadecyltrimethylammonium chloride and bromide (CTAC and CTAB), 1-hexadecylpyridinium chloride and bromide (CPyCl and CPyBr), and benzyldimethylhexadecylammonium chloride (BDMC), which have the same hydrophobic tail.

A Weyl semimetal possesses spin-polarized band-crossings, called Weyl nodes, connected by topological surface arcs. The low-energy excitations near the crossing points behave the same as massless Weyl fermions, leading to exotic properties like chiral anomaly. To have the transport properties dominated by Weyl fermions, Weyl nodes need to locate nearly at the chemical potential and enclosed by pairs of individual Fermi surfaces with non-zero Fermi Chern numbers.

Semifluorinated alkanes form monolayers with interesting properties at the air–water interface due to their pronounced amphi-solvophobic nature and the stiffness of the fluorocarbons. In the present work, using a combination of structural and dynamic probes, we investigated how small molecular changes can be used to control the properties of such an interface, in particular its organization, rheology, and reversibility during compression–expansion cycles.

PbCuTe₂O₆ is a rare example of a spin liquid candidate featuring a three-dimensional magnetic lattice. Strong geometric frustration arises from the dominant antiferromagnetic interaction that generates a hyperkagome network of Cu²⁺ ions although additional interactions enhance the magnetic lattice connectivity.

G.S. Tucker et al., Physical Review B 93, 054401 (2016). Inelastic neutron scattering measurements performed at EIGER and TASP have mapped the magnetic excitation spectrum along high-symmetry directions of the first Brillouin zone for the magnetic skyrmion host copper selenate, Cu₂OSeO₃.

The realization of a controllable metamagnetic transition from AFM to FM ordering would open the door to a plethora of new spintronics based devices that, rather than reorienting spins in a ferromagnet, harness direct control of a materials intrinsic magnetic ordering. In this study FeRh films with drastically reduced transition temperatures and a large magneto-thermal hysteresis were produced for magnetocaloric and spintronics applications.

Polyelectrolyte multilayers (PEMs) with stratification of the internal structure were assembled from statistical amphiphilic copolyelectrolytes of opposite charges. These polyelectrolytes organize in aqueous solutions into micellar structures with fluoroalkyl and aromatic nanodomains, respectively, that were also preserved after deposition as thin films via layer-by-layer (LbL) electrostatic self-assembly.

We show using detailed magnetic and thermodynamic studies and theoretical calculations that the ground state of Ba₃ZnIr₂O₉ is a realization of a novel spin-orbital liquid state. Our results reveal that Ba₃ZnIr₂O₉ with Ir⁵⁺ (5d⁴) ions and strong spin-orbit coupling (SOC) arrives very close to the elusive J 1⁄4 0 state but each Ir ion still possesses a weak moment.

When the energy eigenvalues of two coupled quantum states approach each other in a certain parameter space, their energy levels repel each other and level crossing is avoided. Such level repulsion, or avoided level crossing, is commonly used to describe the dispersion relation of quasiparticles in solids.

Many properties of materials can be changed by varying the interatomic distances in the crystal lattice by applying stress. Ideal model systems for investigations are heteroepitaxial thin films where lattice distortions can be induced by the crystallographic mismatch with the substrate. Here we describe an in situ simultaneous diagnostic of growth mode and stress during pulsed laser deposition of oxide thin films.

The recent discovery of magnetic skyrmion lattices initiated a surge of interest in the scientic community. Several novel phenomena have been shown to emerge from the interaction of conducting electrons with the skyrmion lattice, such as a topological Hall-effect and a spin-transfer torque at ultra-low current densities.

The family of iron-based superconductors has recently acquired a new member material, FeS. Theoretically, this compound has been shown to have electronic structure similar to that of the superconducting FeSe. However, contradictory ground states have been predicted for FeS. In this work, a collaboration of authors from Switzerland and Germany use muon spin rotation and relaxation to show that weak-moment magnetism microscopically coexists with bulk superconductivity.

The phase behavior of nanoparticle (silica)−polymer (polyethylene glycol) system without and with an electrolyte (NaCl) has been studied. It is observed that nanoparticle−polymer system behaves very differently in the presence of electrolyte. In the absence of electrolyte, the nanoparticle−polymer system remains in one-phase even at very high polymer concentrations.

The mechanical performance of materials at oil/water interfaces after consumption is a key factor affecting hydrophobic drug release. In this study, we methylated the surface of nanocrystalline cellulose (NCC) by mercerization and dimethyl sulfate exposure to produce thermosensitive biopolymers. These methylated NCC (metNCC) were used to investigate interfacial thermogelation at air/water and medium-chain triglyceride (MCT)/water interfaces at body temperature.

The present Letter reports on self-diffusion in amorphous silicon. Experiments were done on ²⁹Si/^natSi heterostructures using neutron reflectometry and secondary ion mass spectrometry. The diffusivities follow the Arrhenius law in the temperature range between 550 and 700°C with an activation energy of (4.4 ± 0.3) eV.

The performance and degree of efficiency of industrial transformers are directly influenced by the magnetic properties of high-permeability steel laminations (HPSLs). Industrial transformer cores are built of stacks of single HPSLs. While the insulating coating on each HPSL reduces eddy-current losses in the transformer core, the coating also induces favorable inter-granular tensile stresses that significantly influence the underlying magnetic domain structure.

The transfer rate of a probe molecule across the interfacial layer of a water-in-oil (w/o) microemulsion was investigated using a combination of transverse field muon spin rotation (TF-μSR), avoided level crossing muon spin resonance (ALC-μSR), and Monte Carlo simulations. Reverse micro-emulsions consist of nanometer-sized water droplets dispersed in an apolar solvent separated by a surfactant monolayer.

In pulsed laser deposition the use of a rectangular or elliptical beam spot with a non 1:1 aspect ratio leads to the so called flip-over effect. Here, the longest dimension of the laser spot results in the shortest direction of plasma plume expansion.

The mechanical properties of many materials are based on the macroscopic arrangement and orientation of their nanostructure. This nanostructure can be ordered over a range of length scales. In biology, the principle of hierarchical ordering is often used to maximize functionality, such as strength and robustness of the material, while minimizing weight and energy cost.

We report microscopic studies by muon spin rotation/relaxation as a function of pressure of the Ca₃Ir₄Sn₁₃ and Sr₃Ir₄Sn₁₃ cubic compounds, which are members of the (Ca_1−xSr_x)₃Ir₄Sn₁₃ system displaying superconductivity and a structural phase transition associated with the formation of a charge density wave (CDW).