Related papers: Microstructure and Fe-vacancy ordering in the KFex…
With single crystal X-ray diffraction studies, we compare the structures of three sample showing optimal superconductivity, K0.774(4)Fe1.613(2)Se2, K0.738(6)Fe1.631(3)Se2 and Cs0.748(2)Fe1.626(1)Se2. All have an almost identical ordered…
The discovery of superconductivity in alkali-ammonia co-intercalated FeSe has generated intensive interest because of their highest Tc (~ 45 K) among iron-chalcogenide superconductors with bulk form. Here, we report the phase diagrams of…
We investigate the orbitally resolved superconducting properties of bulk FeSe using scanning tunneling microscopy (STM). We find that the spectral weights of both the large $\Delta_1$ and small $\Delta_2$ superconducting gaps remain nearly…
There is an ongoing debate about the relative importance of structural change versus doping charge carriers on the mechanism of superconductivity in Fe-based materials. Elucidating this issue is a major challenge since it would require a…
Motivated by the discovery of superconductivity in F-doped LaFeAsO, we investigated the magnetic fluctuations in a related compound Fe(Se1-xTex)0.92 (x = 0.75, 1) using neutron scattering techniques. Non-superconducting FeTe0.92 shows…
We report on the synthesis of large single crystals of a new FeSe-layer superconductor Cs0.8(FeSe0.98)2. X-ray powder diffraction, neutron powder-diffraction and magnetization measurements have been used to compare the crystal structure and…
In amorphous superconductors, superconducting and vortex pinning properties are strongly linked to the absence of long range order. Consequently, superconductivity and vortex phases can be studied to probe the underlying microstructure and…
The magnetic structure of superconducting Eu(Fe0.82Co0.18)2As2 is unambiguously determined by single-crystal neutron diffraction. A long-range ferromagnetic order of the Eu2+ moments along the c-direction is revealed below the magnetic…
Single crystals of Fe(1+x)Te(1-y)Se(y) have been grown with a controlled Fe excess and Se doping, and the crystal structure has been refined for various compositions. The systematic investigation of magnetic and superconducting properties…
X-ray diffraction experiments were performed on polycrystalline and single-crystal specimens of Ce$_{2}$Fe$_{17}$ at temperatures between 10 K and 300 K. Below $T_{\mathrm{t}}$ = 118$\pm$2 K, additional weak superstructure reflections were…
Single crystal synchrotron X-ray diffraction as a function of temperature and pressure has revealed a complex biphase mixture in superconducting FeSe. Based on our experimental results we construct a phase diagram where structural behavior…
Exploration of new superconductors has always been one of the research directions in condensed matter physics. We report here a new layered heterostructure of [(Fe,Al)(OH)2][FeSe]1.2, which is synthesized by the hydrothermal ion-exchange…
The newly discovered superconductor FeSe1-x (x=0.08, Tconset=13.5 K at ambient pressure rising to 27 K at 1.48 GPa) exhibits a structural phase transition from tetragonal to orthorhombic below 70 K at ambient pressure - the crystal…
We investigated the magnetization and crystal structure of FeSe polycrystalline samples with various grain sizes. For the samples with large grains, a large magnetic critical current density Jc was observed. For the samples with small…
High-pressure magnetization, structural and 57Fe M\"ossbauer studies were performed on superconducting Rb0.8Fe1.6Se2.0 with Tc = 32.4 K. The superconducting transition temperature gradually decreases on increasing pressure up to 5.0 GPa…
The interplay of different electronic phases underlies the physics of unconventional superconductors. One of the most intriguing examples is a high-Tc superconductor FeTe1-xSex: it undergoes both a topological transition, linked to the…
Complex conductivity measurements spanning the entire temperature range, including the vicinity of $T_c$, were conducted on systematically varied FeSe$_{1-x}$Te$_x$ ($x$ = 0 - 0.5) very thin films. By applying a novel cavity measurement…
We report significantly enhanced magnetic moment in K0.69(2)Fe1.45(1)Se2.00(1) single crystals with sharp Tc and bulk superconductivity obtained by postannealing and quenching process. There are two Fe sites in the…
In contrast to its bulk crystals, the FeSe film or layer exhibits better superconductivity performance, which attract much interest in its fundamental research as well as potential application. In present work, transition from insulator to…
The latest discovery of a new iron-chalcogenide superconductor A$_x$Fe$_{2-y}$Se$_2$(A=K, Cs, Rb, Tl and etc.) has attracted much attention due to a number of its unique characteristics, such as the possible insulating state of the parent…