In Situ Local Imaging of Ferromagnetism and Superconductivity in RbEuFeAs.

The coexistence of superconductivity and ferromagnetism is an intrinsically interesting research focus in condensed matter physics, but the study is limited by low superconducting () and magnetic () transition temperatures in related materials. Here, we used a scanning superconducting quantum interference device to image the in situ diamagnetic and ferromagnetic responses of RbEuFeAs with high and . We observed significant suppression of the superfluid density in the vicinity of the magnetic phase transition, signifying fluctuation-enhanced magnetic scatterings between Eu spins and Fe 3d conduction electrons.

Superconductivity and Charge-Density-Wave-Like Transition in ThCuAs.

We report the synthesis, crystal structure, and physical properties of a novel ternary compound, ThCuAs. The material crystallizes in a tetragonal structure with lattice parameters = 4.0639(3) Å and = 24.

Orthorhombic charge density wave on the tetragonal lattice of EuAl.

EuAl possesses the BaAl crystal structure type with tetragonal symmetry 4/. It undergoes a charge density wave (CDW) transition at  = 145 K and features four consecutive antiferromagnetic phase transitions below 16 K. Here we use single-crystal X-ray diffraction to determine the incommensurately modulated crystal structure of EuAl in its CDW state.

A Noncentrosymmetric Polymorph of LuRuGe.

We report a new polymorph of LuRuGe, obtained in indium flux. This phase exhibits the noncentrosymmetric ZrNiAl-type structure with the space group 6̅2 as determined by single-crystal X-ray diffraction. This polymorph can convert into another centrosymmetric polymorph (TiNiSi-type structure, space group ) at high temperatures.

Antiferromagnetic Semiconductor BaFMnTe with Unique Mn Ordering and Red Photoluminescence.

Semiconductors possessing both magnetic and optoelectronic properties are rare and promise applications in opto-spintronics. Here we report the mixed-anion semiconductor BaFMnTe with a band gap of 1.76 eV and a work function of 5.

Unconventional Defects in a Quasi-One-Dimensional KMnBi.

Quasi-one-dimensional (Q1D) structures comprising a compact array of indefinitely long 1D nanowires (NWs) are scarce, especially in a bulk device-scale showing metallic and semiconducting behaviors along different axes. Unlike plentiful observations of nature of defects in three-/two-dimensional materials, there is a notable paucity of such reports in Q1D. Herein we present unconventional motific defects and their properties in a bulk Q1D KMnBi crystal, in which an individual NW motif acts as one body.

Pressure-Induced Superconductivity and Flattened Se Rings in the Wide Band Gap Semiconductor CuISe.

The two major classes of unconventional superconductors, cuprates and Fe-based superconductors, have magnetic parent compounds, are layered, and generally feature square-lattice symmetry. We report the discovery of pressure-induced superconductivity in a nonmagnetic and wide band gap 1.95 eV semiconductor, CuISe, with a unique anisotropic structure composed of two types of distinct molecules: Se rings and CuI dimers, which are linked in a three-dimensional framework.

KCuP: A Two-Dimensional Noncentrosymmetric Metallic Pnictide.

We report a 2D material, KCuP, with a noncentrosymmetric structure (trigonal space group 31, = 6.9637(2) Å, = 24.1338 (10) Å), which forms both from a molten potassium polyphosphide flux and from the elements.

Orbital-flop Induced Magnetoresistance Anisotropy in Rare Earth Monopnictide CeSb.

The charge and spin of the electrons in solids have been extensively exploited in electronic devices and in the development of spintronics. Another attribute of electrons-their orbital nature-is attracting growing interest for understanding exotic phenomena and in creating the next-generation of quantum devices such as orbital qubits. Here, we report on orbital-flop induced magnetoresistance anisotropy in CeSb.

A Natural 2D Heterostructure [PbSbS][Au Te] with Large Transverse Nonsaturating Negative Magnetoresistance and High Electron Mobility.

We report the two-dimensional (2D) natural heterostructure [PbSbS][Au Te] ( x = 0.52-0.36) which shows anomalous, transverse nonsaturating negative magnetoresistance (MR).

High Hole Mobility and Nonsaturating Giant Magnetoresistance in the New 2D Metal NaCuSe Synthesized by a Unique Pathway.

The new compound NaCuSe forms by the reaction of CuO and Cu in a molten sodium polyselenide flux, with the existence of CuO being unexpectedly critical to its synthesis. It adopts a layered hexagonal structure (space group P6/ mmc with cell parameters a = 3.9931(6) Å and c = 25.

Anisotropic upper critical magnetic fields in RbCrAs superconductor.

RbCrAs is a structurally one-dimensional superconductor containing CrAs chains with a superconducting transition temperature of [Formula: see text] K. Here we report the electrical resistance measurements for RbCrAs single crystals, under magnetic fields up to 29.5 T and at temperatures down to 0.

Coexistence of superconductivity and complex 4 f magnetism in Eu0.5Ce0.5BiS2F.

EuBiS2F is a self-doped superconductor due to the mixed valence of Eu. Here we report that, with the Ce substitution for Eu by 50 at.%, the material exhibits ferromagnetic ordering at 8 K for the Ce-4 f moment, superconductivity at 2.

Multiband superconductivity in Ta4Pd3Te16 with anisotropic gap structure.

We carried out measurements of the magnetoresistance, magnetic susceptibility and specific heat on crystals of the low-dimensional transition metal telluride Ta4Pd3Te16. Our results indicate that Ta4Pd3Te16 is an anisotropic type-II superconductor in the clean limit with the extracted Ginzburg-Landau parameter KGL = 84. The upper critical field Hc2(T) shows an anomalous temperature dependence at low temperatures and the anisotropy of Hc2(T) is strongly T-dependent, both of which indicate a multiband scenario.

NMR investigation of the quasi-one-dimensional superconductor K(2)Cr(3)As(3).

We report ^{75}As NMR measurements on the new quasi-one-dimensional superconductor K_{2}Cr_{3}As_{3} (T_{c}∼6.1  K) [J. K.

Anomalous Eu valence state and superconductivity in undoped Eu3Bi2S4F4.

We have synthesized a novel europium bismuth sulfofluoride, Eu3Bi2S4F4, by solid-state reactions in sealed evacuated quartz ampules. The compound crystallizes in a tetragonal lattice (space group I4/mmm, a = 4.0771(1) Å, c = 32.

Design and synthesis of a new layered thermoelectric material LaPbBiS3O.

A new quinary oxysulfide LaPbBiS3O was designed and successfully synthesized via a solid-state reaction in a sealed evacuated quartz tube. This material, composed of stacked NaCl-like [M4S6] (where M = Pb, Bi) layers and fluorite-type [La2O2] layers, crystallizes in the tetragonal space group P4/nmm with a = 4.0982(1) Å, c = 19.

Variable range hopping conductivity and spin glass behavior in spin-ladder Ba0.6K0.4Fe2Se3 single crystals.

Ba0.6K0.4Fe2Se3 (BKFS) single crystals were investigated by means of measurements of powder x-ray diffraction, temperature-dependent resistivity, anisotropic dc magnetization, ac magnetic susceptibility and specific heat.

Growth and characterizations of BaTiFeAsO single crystals.

Single crystals of a new iron-based superconductor BaTiFeAsO have been grown successfully via a BaAs-flux method in a sealed evacuated quartz tube. Bulk superconductivity with ∼ 21.5 K was demonstrated in resistivity and magnetic susceptibility measurements after the as-grown crystals were annealed at 500 °C in vacuum for a week.

Ba2Ti2Fe2As4O: A new superconductor containing Fe2As2 layers and Ti2O sheets.

We have synthesized a new oxypnictide, Ba2Ti2Fe2As4O, via a solid-state reaction under a vacuum. The compound crystallizes in a body-centered tetragonal lattice, which can be viewed as an intergrowth of BaFe2As2 and BaTi2As2O, thus containing Fe2As2 layers and Ti2O sheets. Bulk superconductivity at 21 K is observed after annealing the as-prepared sample at 773 K for 40 h.