Related papers: Two-step phase transitions in Fe(Se,Te)
We performed $^{77}$Se-NMR measurements on FeSe$_{1-x}$S$_x$, ($x$ = 0.12) up to 3.0 GPa at an applied magnetic field of 6.02 T, and found that the superconducting (SC) phase exhibits a remarkable double-dome structure in the…
We report on the structural phase transitions in the S doped FeSe superconductor by powder synchrotron X ray diffraction at high pressures up to 18.5 GPa under compression and decompression modes. In order to create high quasi hydrostatic…
We report $^{75}$As NMR studies on single crystals of rare-earth doped iron pnictides superconductor Ca$_{1-x}$Pr$_{x}$Fe$_{2}$As$_{2}$ ($x$=0.075 and 0.15). The $^{75}$As spectra show a chemical pressure effect with doping and a first…
At ambient pressure CaFe2As2 has been found to undergo a first order phase transition from a high temperature, tetragonal phase to a low temperature orthorhombic / antiferromagnetic phase upon cooling through T ~ 170 K. With the application…
CaFe$_2$As$_2$ has been synthesized and found to form in the tetragonal, ThCr$_2$Si$_2$ structure with lattice parameters $a = 3.912(68) \AA$ and $c = 11.667(45) \AA$. Upon cooling through 170 K, CaFe$_2$As$_2$ undergoes a first order,…
In common with other iron-based high temperature superconductors, FeSe exhibits a transition to a ``nematic'' phase below 90Kelvin in which the crystal rotation symmetry is spontaneously broken. However, the absence of strong low-frequency…
Temperature (12K $\le$ T $\le$ 300K) dependent extended X-ray absorption fine structure (EXAFS) studies at the Fe K edge in FeSe$_{1-x}$Te$_x$ (x = 0, 0.5 and 1.0) compounds have been carried out to understand the reasons for increase in…
Transport and magnetic studies of PbTaSe$_2$ under pressure suggest existence of two superconducting phases with the low temperature phase boundary at $\sim 0.25$ GPa that is defined by a very sharp, first order, phase transition. The first…
With the proposed Hund's rule correlation picture, i.e. the fluctuating Fe local moments with the As-bridged antiferromagnetic superexchange interactions, the exceptional collapsed tetragonal phase and related phase transitions observed in…
We studied the anisotropy in physical properties of Ba1.00(4)Fe1.9(1)Se3.1(1) single crystals. BaFe2Se3 is a semiconductor below 300 K. Magnetization measurements show that there is a crossover from short-range antiferromagnetic (AFM)…
The Fe-based superconducting KxFe2-ySe2 (0.6 {\leg} x {\leg} 1, 0.2{\leg} y {\leg} 0.4) compounds, unlike the well-known RFe2As2 (R = Ba, Sr, Ca) superconductors, contain complex structural features and notable physical properties, such as…
The nematic electronic state and its associated nematic critical fluctuations have emerged as potential candidates for superconducting pairing in various unconventional superconductors. However, in most materials their coexistence with…
Potassium intercalated FeSe has been reported as a superconductor with superconducting transition temperatures ($T_{\rm c}$'s) of 30-48 K. However, there is no clear answer to identify the relationship between the surface morphology,…
The phase diagram of several itinerant ferromagnets reveals the common feature. The phase transition temperature decreases with pressure increase and reaches zero value at some critical pressure $P_c$ such that at low enough temperatures…
The results of differential-thermal analysis of various samples as well as dielectric measurements of solid solutions $TlIn_{1-x}Fe_x^{56,57}S_2$ are presented. It has been established that phase transitions become blurred and shift to low…
The electronic structure of FeSe, the simplest iron based superconductor (Fe-SC), conceals a potential of dramatic increase of Tc that realizes under pressure or in a single layer film. This is also the system where nematicity, the…
La$_{0.4}$Na$_{0.6}$Fe$_2$As$_2$ single crystals have been grown out of an NaAs flux in an alumina crucible and characterized by measuring magnetic susceptibility, electrical resistivity, specific heat, as well as single crystal x-ray and…
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$2 K, additional weak superstructure reflections were…
Elastic neutron scattering on a single crystal and powder X-ray diffraction measurements were carried out to investigate how the crystal structure evolves as a function of temperature in the Weyl semimetal WTe$_{2}$. A sharp transition from…
Iron-based superconductors are well-known for their intriguing phase diagrams, which manifest a complex interplay of electronic, magnetic and structural degrees of freedom. Among the phase transitions observed are superconducting, magnetic,…