Magnetic and superconducting properties of FeSe1−xTex (x∼0, 0.5, and 1.0)

Abstract

Magnetization studies for FeSe 1-x Te x (x 0, 0.5, and 1.0) compounds were carried out in magnetic fields up to 50 kOe and in the temperature range 2-300 K. The superconducting transition was observed at T c 8 K and 13.6-14.2 K in FeSe 0.963 and FeSe 0.5 Te 0.5 , respectively. For the most samples, a nonlinear behavior of the magnetization curves in the normal state gives evidence of a commonly observed substantial presence of ferromagnetic impurities in the compounds under study. By taking these impurity effects into account, the intrinsic magnetic susceptibility χ of FeSe 0.963 , FeSe 0.5 Te 0.5 , and FeTe was estimated to increase gradually with Te content. For FeTe a drastic drop in χ(T) with decreasing temperature was found at T N 70 K, which is presumably related to antiferromagnetic ordering. To shed light on the observed magnetic properties, ab initio calculations of the exchange enhanced magnetic susceptibility are performed for FeSe and FeTe within the local spin density approximation.

Synthesis, crystal structure, and magnetism ofβ-Fe1.00(2)Se1.00(Hu1, Lei2, Abeykoon3 et al. 2011Phys. Rev. B641390View full textAdd to dashboardCite

“…was ascribed to traces of Fe impurity at ambient pressure due to its weak nature, 25,26 or was not detected. 9,27 In our crystals, s -shape of M(H) for H (101) (Fig.…”

Iron-based superconductors: Magnetism, superconductivity, and electronic structure (Review Article)

“…The FeSe has been found to superconduct at approximately 8 K [74], and up to 37 K under pressure [75]. Fe 1+y Se x Te 1-x shows maximum c T about 14 K at = 0.5 x [21,73,76]. The crystals grow with excess ( y ) Fe atoms that present beyond those needed to fill the Fe square lattice layers and go into interstitial positions within the Te layers [7].…”

Superconducting, magnetic and magnetotransport properties of FeTe1-xSex single crystals

“…15,39,43,44 This transition may also be due to presence of small amount of Fe 3 O 4 phase in the sample which could not be detected in the XRD results. 7 To study the field dependent critical current density, J C (H), the field dependent magnetization measurements (M-H) of samples FTS0.40 and FTS0.50 samples have been done at 5 K temperature by applying the magnetic field along the c-axis in the range 0 to ±7 T (see Fig. 4(a)).…”

“…[7][8][9][23][24][25][26][27] Highest T C (∼15 K) is observed when Se substitutes for Te in FeTe system with the composition FeTe 1-x Se x (x = 0.5). [7][8][9]28 As this compound has an extremely simple crystal structure, excellent response to external pressure and the less toxic Se in comparison to As in pnictides, it presents a better model to study the interplay between structure, superconductivity and magnetism in the Fe-based superconducting compounds. In the present paper we have made an attempt to grow single crystalline samples of Se doped FeTe compound using self-flux technique and studied the structural, electrical and magnetic properties of the as-grown crystals.…”

“…The maximum T C observed in FeSe(Te) system is ∼15 K at ambient pressure. [7][8][9] Under the applied pressure of 1.48 GPa, T C can rise up to 27 K, 10 suggesting that this simple binary FeSe(Te) compound may have some essential ingredients for attaining high temperature superconductivity. It is observed that the structural and magnetic properties of this system depend very sensitively on the Se/Te:Fe ratio.…”