We discover a robust coexistence of superconductivity and ferromagnetism in an iron arsenide RbEuFe4As4. The new material crystallizes in an intergrowth structure of RbFe2As2 and EuFe2As2, such that the Eu sublattice turns out to be primitive instead of being body-centered in EuFe2As2. The FeAs layers, featured by asymmetric As coordinations, are hole doped due to charge homogenization. Our combined measurements of electrical transport, magnetization and heat capacity unambiguously and consistently indicate bulk superconductivity at 36.5 K in the FeAs layers and ferromagnetism at 15 K in the Eu sublattice. Interestingly, the Eu-spin ferromagnetic ordering belongs to a rare third-order transition, according to the Ehrenfest classification of phase transition. We also identify an additional anomaly at ∼ 5 K, which is possibly associated with the interplay between superconductivity and ferromagnetism.further revised the electronic phase diagram because of the discovery of a reentrant spin glass state. Recent x-ray resonant magnetic scattering[3] and neutron scattering[4] experiments however indicated long-range ferromagnetic orderings for Eu spins in superconducting EuFe 2 (As 1−x P x ) 2 with x = 0.19 and 0.15, respectively. It was demonstrated that the Eu spins align exactly along the c axis, in contradiction to the spin-canting scenario. So far, this discrepancy remains unresolved. Note that the spin-tilting angle (∼20 • from the c axis, as detected by Mössbauer measurements[2]) coincides with the direction that connects the interlayer next-nearest (NN) Eu atoms because of the body-centered Eu sublattice. To clarify whether the Eu-sublattice type is relevant to Eu spin orientations, it is desirable to study a related material system in which Eu atoms form a primitive tetragonal lattice.Local-moment FM and spin-singlet SC are known to be mutually incompatible [20][21][22], which makes their coexistence (hereafter abbreviated as FM+SC) very rare [23]. The FM+SC phenomenon observed in FeSCs has been ascribed to the multi-orbital character as well as the robustness of superconductivity against magnetic fields [10,24]. On the one hand, the zero-temperature upper critical magnetic field, H c2 (0), of FeSCs is typically higher than 50 T [25,26], which is large enough to fight the internal exchange field that is comparable to the hyperfine field on the Eu nucleus (∼ 25 T) [2]. On the other hand, the Eu-spin FM can be satisfied even in the presence of SC, because the Fe-3d multi-orbitals enable both superconducting pairing (dominated by the d yz and d zx electrons [27]) and the Ruderman-Kittel-Kasuya-Yosida (RKKY) exchange interaction between Eu local moments. The RKKY interaction can be mediated arXiv:1605.04396v3 [cond-mat.supr-con]

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We show how temperature-induced disorder can be combined in a direct way with first-principles scattering theory to study diffusive transport in real materials. Excellent (good) agreement with experiment is found for the resistivity of Cu, Pd, Pt (and Fe) when lattice (and spin) disorder are calculated from first principles. For Fe, the agreement with experiment is limited by how well the magnetization (of itinerant ferromagnets) can be calculated as a function of temperature. By introducing a simple Debye-like model of spin disorder parameterized to reproduce the experimental magnetization, the temperature dependence of the average resistivity, the anisotropic magnetoresistance and the spin polarization of a Ni80Fe20 alloy are calculated and found to be in good agreement with existing data. Extension of the method to complex, inhomogeneous materials as well as to the calculation of other finite-temperature physical properties within the adiabatic approximation is straightforward.PACS numbers: 72.10. Di, Introduction.-Measuring the temperature dependence of electrical transport is one of the most important and common experimental probes of condensed matter. Although a great deal of what determines the temperature dependence is understood qualitatively [1], there has been virtually no progress in translating this understanding into quantitative, material-specific studies in the past twenty years because of the complexity of the theoretical formalisms [2, 3]; the lowest order variational approximation (LOVA) that is the basis for the successful description of the temperature-dependent electrical and thermal resistivities of a number of elemental metals [3] has to the best of our knowledge not been applied to more complex materials. In particular, it has not been extended to the study of magnetic materials. The need to be able to do so is pressing because current studies of magnetization switching involve large threshold current densities that are accompanied by substantial Joule heating [4].Inspired by the success of the "direct" ab initio molecular dynamics approach to studying structural and electronic properties of matter at finite temperatures introduced by Car and Parrinello [5], we have developed a direct approach to calculate finite-temperature transport properties within the adiabatic approximation. For nonmagnetic (NM) materials, we generate "snapshots" of a thermally disordered solid [6] and use first-principles scattering theory to determine the scattering matrix [7,8] and related properties [9], Fig. 1(a). The results of this two-stage procedure are illustrated by comparing the calculated and experimentally measured temperaturedependent resistivities of the NM metals Cu, Pd and Pt in Fig. 1(b). The purpose of this Letter is to underpin and extend these extremely promising results by including spin-orbit coupling (SOC) [10][11][12][13][14] to determine the temperature dependence of the spin-flip diffusion lengths

The intrinsically hole-doped RbEuFe4As4 exhibits bulk superconductivity at Tsc = 36.5 K and ferromagnetic ordering in the Eu sublattice at Tm = 15 K. Here we present a hole-compensation study by introducing extra itinerant electrons via a Ni substitution in the ferromagnetic superconductor RbEuFe4As4 with Tsc > Tm. With the Ni doping, Tsc decreases rapidly, and the Euspin ferromagnetism and its Tm remain unchanged. Consequently, the system RbEu(Fe1−xNix)4As4 transforms into a superconducting ferromagnet with Tm > Tsc for 0.07 ≤ x ≤ 0.08. The occurrence of superconducting ferromagnets is attributed to the decoupling between Eu 2+ spins and superconducting Cooper pairs. The superconducting and magnetic phase diagram is established, which additionally includes a recovered yet suppressed spin-density-wave state.

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Imidazole was introduced into the channels of the metal-organic framework UiO-67 using an evaporation method. The imidazole@UiO-67 composite presents a high proton conductivity of 1.44 × 10(-3) S cm(-1) at 120 °C under anhydrous conditions. With a low activation energy at high temperatures (0.36 eV), the hybrid material can be regarded as a superionic conductor.

A general method for producing low-fouling biomaterials on any surface by surface-initiated grafting of polymer brushes is presented. Our procedure uses radiofrequency glow discharge thin film deposition followed by macro-initiator coupling and then surface-initiated atom transfer radical polymerization (SI-ATRP) to prepare neutral polymer brushes on planar substrates. Coatings were produced on substrates with variable interfacial composition and mechanical properties such as hard inorganic/metal substrates (silicon and gold) or flexible (perfluorinated poly(ethylene-co-propylene) film) and rigid (microtitre plates) polymeric materials. First, surfaces were functionalized via deposition of an allylamine plasma polymer thin film followed by covalent coupling of a macro-initiator composed partly of ATRP initiator groups. Successful grafting of a hydrophilic polymer layer was achieved by SI-ATRP of N,N'-dimethylacrylamide in aqueous media at room temperature. We exemplified how this method could be used to create surface coatings with significantly reduced protein adsorption on different material substrates. Protein binding experiments using labelled human serum albumin on grafted materials resulted in quantitative evidence for low-fouling compared to control surfaces.

The tea plant is known as a fluorine accumulator. Fluoride (F) content in fresh leaves collected from 14 plantations in China was investigated. The F increased with maturity, and the F variation was remarkable in the tender shoots. Furthermore, significant negative relationships were observed between F content and the content of the quality parameters total polyphenols and amino acids. These substances are rich in young leaves and poor in mature ones. With regard to quality of tea products, the relationship with F content was studied using 12 brands of tea products in four categories: green tea, oolong tea, black tea, and jasmine tea collected from six provinces. The F level increased with the decline in quality and showed good correlation with the quality grades. The results suggest that the F content could be used as a quality indicator for tea evaluation.