The authors report on the discovery of a magnetically soft high‐entropy alloy of composition FeCoNiPdCu, which performs comparably to the best commercial soft magnets for static and low‐frequency applications. Properly heat‐treated FeCoNiPdCu develops nanostructure that can be viewed as a two‐phase bulk nanocomposite of randomly intermixed FeCoNi magnetic domains and PdCu nonmagnetic “spacers”, both of 2–5 nm cross dimensions. Due to the nanometric size, the FeCoNi domains are magnetically single‐domain particles, and since the particles are exchange‐coupled across the boundaries, exchange averaging of magnetic anisotropy takes place, resulting in an almost vanishing coercive field and excellent magnetic softness. The formation of a two‐phase nanostructure favorable for the exchange averaging of magnetic anisotropy is a consequence of specific values of the binary mixing enthalpies for the chosen elements. Though high‐entropy alloys are generally considered to be random solid solutions of multiple elements on a topologically ordered crystal lattice, clustering of the atoms into preferential chemical environments on a nanoscale essentially determines their magnetic properties. Experimentally, the magnetic properties of the FeCoNiPdCu high‐entropy alloy are compared to the commercial, magnetically soft non‐oriented silicon electrical steel.

We investigated molecular dynamics in two ammonium borane systems from the group of promising ion conductors. The investigation was performed by means of 1 H and 11 B NMR spectroscopy and spin−lattice relaxation techniques. We identified two reorientational processes, the rotations of NH 4 units that are present already at low temperatures and rotations of large boron cages, B 10 H 10 or B 12 H 12 , which are thermally activated and become prominent above 250 K. Activation energies for these processes were determined. In addition, solid-state ion conductivity measurements were conducted to determine poor NH 4 + conductivity of both systems.

The new phase Be 3 Ru crystallizes with TiCu 3 -type structure (space group Pmmn (59), a = 3.7062(1) Å, b = 4.5353(1) Å, c = 4.4170(1) Å), a coloring variant of the hexagonal closest packing (hcp) of spheres. The electronic structure revealed that Be 3 Ru has a pseudo-gap close to the Fermi level. A strong charge transfer from Be to Ru was observed from the analysis of electron density within the Quantum Theory of Atoms in Molecules (QTAIM) framework and polar three-and four-atomic BeÀ Ru bonds were observed from the ELIÀ D (electron localizability indicator) analysis. This situation is very similar to the recently investigated Be 5 Pt and Be 21 Pt 5 compounds. The unusual crystal chemical feature of Be 3 Ru is that different charged species belong to the same closest packing, contrary to typical inorganic compounds, where the cationic components are located in the voids of the closest packing formed by anions. Be 3 Ru is a diamagnet displaying metallic electrical resistivity.

High-entropy alloys (HEAs) are characterized by a simultaneous presence of a crystal lattice and an amorphous-type chemical (substitutional) disorder. In order to unravel the effect of crystal-glass duality on the electronic transport properties of HEAs, we performed a comparative study of the electronic transport coefficients of a 6-component alloy Al0.5TiZrPdCuNi that can be prepared either as a HEA or as a metallic glass (MG) at the same chemical composition. The HEA and the MG states of the Al0.5TiZrPdCuNi alloy both show large, negative-temperature-coefficient resistivity, positive thermopower, positive Hall coefficient and small thermal conductivity. The transport coefficients were reproduced analytically by the spectral conductivity model, using the Kubo-Greenwood formalism. For both modifications of the material (HEA and MG), contribution of phonons to the transport coefficients was found small, so that their temperature dependence originates predominantly from the temperature dependence of the Fermi–Dirac function and the variation of the spectral conductivity and the related electronic density of states with energy within the Fermi-level region. The very similar electronic transport coefficients of the HEA and the MG states point towards essential role of the immense chemical disorder.