Author:
Tian Long,Liu Panpan,Hong Tao,Seydel Tilo,Lu Xingye,Luo Huiqian,Li Shiliang,Dai Pengcheng
Abstract
The iron-chalcogenide superconductor FeTe1–x
Se
x
displays a variety of exotic features distinct from iron pnictides. Although much effort has been devoted to understanding the interplay between magnetism and superconductivity near x = 0.5, the existence of a spin glass phase with short-range magnetic order in the doping range (x ∼ 0.1–0.3) has rarely been studied. Here, we use DC/AC magnetization and (quasi) elastic neutron scattering to confirm the spin-glass nature of the short-range magnetic order in a Fe1.07Te0.8Se0.2 sample. The AC-frequency dependent spin-freezing temperature T
f generates a frequency sensitivity ΔT
f(ω)/[T
f(ω)Δlog10
ω] ≈ 0.028 and the description of the critical slowing down with τ = τ
0(T
f/T
SG – 1)−z v
gives T
SG ≈ 22 K and zv ≈ 10, comparable to that of a classical spin-glass system. We have also extended the frequency-dependent T
f to the smaller time scale using energy-resolution-dependent neutron diffraction measurements, in which the T
N of the short-range magnetic order increases systematically with increasing energy resolution. By removing the excess iron through annealing in oxygen, the spin-freezing behavior disappears, and bulk superconductivity is realized. Thus, the excess Fe is the driving force for the formation of the spin-glass phase detrimental to bulk superconductivity.
Subject
General Physics and Astronomy
Cited by
1 articles.
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