Mössbauer Studies on the FeSe System

Abstract

Binary alloys of the FeSex system have been prepared with x possessing the values 1.00, 1.04, 1.08, 1.12, 1.16, 1.25, 1.50, 1.75, and 2.00. Mössbauer spectra at room temperature have been taken for all and at liquid nitrogen temperature for some of them. The effect of thermal treatment is also investigated. The spectra are mostly quadrupole split or single lines, except for the compositions FeSe1.08 to FeSe1.16, which show magnetic hyperfine splitting. The iron ion exists in the high spin 2+ state for the entire system, with varying degrees of covalency.

Electronic and magnetic phase diagram of β-Fe1.01Se with superconductivity at 36.7 K under pressure

“…20%, a distinct different isomer shift, δ = 0.84 mms -1 , and a quadrupole splitting of ΔE Q = 0.21 (2) mms -1 . These values of hyperfine parameters are characteristic of formally divalent Fe in more symmetric surrounding with less covalency and can be unambiguously attributed to the hexagonal phase of FeSe [24], present in the XRD pattern (Fig. 1) (see Fig.…”

XRD, DSC, MS and RS studies of Fe75Se25 iron selenide prepared by mechano-synthesis

“…The spectrum of the sample milled for 3 h was fitted by one sextet with relative absorption area of 62%, which maintained the same BCC Fe parameter, a couple of sextets with relative absorption area of approximately 10% each, indicating the presence of both A and B sites of iron magnetite (Fe 3 O 4 ), and two doublets that were successfully set with parameters of the FeSe and FeSe 2 phases [17][18][19][20]. The relative absorption areas of the doublets were 10% (FeSe) and 6% (FeSe 2 ).…”

Mössbauer spectroscopy evidence for the lack of iron magnetic moment in superconducting FeSe

“…Iron-based superconductors belong to pnictides or chalcogenides and these compounds have been already investigated in the past [3][4][5]. The simplest superconductor of this class belongs to the iron-selenium system, as it is simple binary system [6].…”