Excess-iron driven spin glass phase in Fe1+yTe1-xSex

• 作者: Long Tian Panpan Liu Yao Hong Tilo Seydel Xingye Lu Huiqian Luo Shiliang Li Pengcheng Dai
• 来源期刊: 中国物理B（英文版）
• 年，卷（期）: 2021,（8）
• 所属期刊栏目: RAPID COMMUNICATION
• 页码范围: 189-196
• 页数: 8页
• 语种: 英文
• DOI: 10.1088/1674-1056/ac0695

摘要

The iron-chalcogenide superconductor FeTe1-xSex 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 Tf generates a frequency sensitivity ΔTf(ω)/[Tf(ω)Δlog10ω]≈ 0.028 and the description of the critical slowing down with τ =τo (Tf/TSG-1)-zv gives TSG ≈ 22 K and zv≈ 10,comparable to that of a classical spin-glass system.We have also extended the frequency-dependent Tf to the smaller time scale using energy-resolution-dependent neutron diffraction mea-surements,in which the TN 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 superconduc-tivity is realized.Thus,the excess Fe is the driving force for the formation of the spin-glass phase detrimental to bulk superconductivity.