Structural, Electrical and Magnetic Behaviour of FeTe0.5Se0.5 Superconductor

Solid state synthesis and characterization of bulk FeTe0.5Se0.5superconductors

“…It can be seen that polycrystalline FTS-2 sample has mainly a ferromagnetic background due to ferromagnetic nature of Fe, which yields more dominant ferromagnetic signal than the diamagnetic signal. In general, this indicates the absence of bulk superconductivity in the samples, as obtained by the other research groups [35][36][37][38][39][40][41]. The lower critical field (H c1 ) is an important superconducting parameter where the magnetic field starts to penetrate in to the sample and accordingly vortexes consist of on the sample surface as expected.…”

“…These values are slightly higher than the literature value [40]. The theoretical value of H c2 (T) was also calculated using an equation which is developed by Wen et.al.…”

Photoemission studies of the near EFspectral weight shifts in FeSe1−xTexsuperconductor

“…The stoichiometric compositions of the samples studied using X-ray diffraction and resistivity measurements have been published earlier [19]. It should be noted that the samples contain no excess Fe and are of single phase nature.…”

“…The experimental lattice parameters at 300K were used in the calculations [19]. The correlation effects of the Fe-d orbitals were taken into account by using LDA+U formulism with J as 0.9 eV [12], and U as 3.5 eV for FeTe and 4.0 eV for FeSe [21].…”

Pseudogap behaviour in FeTe and FeSe probed by photoemission

“…Polycrystalline samples of FeSe 1-x Te x (x = 0, 1)and FeSe were synthesized via solid state reaction route [8] and characterized using XRD and resistivity measurements [9]. Angle integrated ultraviolet photoemission measurements were performed at 300 K and 77 K using high intensity VUV source (He I (21.2 eV) and He II (40.8 eV) ) and a hemispherical electron energy analyser (SCIENTA R3000).…”