In-plane magnetic field effect on the neutron spin resonance in optimally doped FeSe$_{0.4}$Te$_{0.6}$ and BaFe$_{1.9}$Ni$_{0.1}$As$_{2}$ superconductors

Shiliang Li; Xingye Lu; Meng Wang; Hui-qian Luo; Miaoyin Wang; Chenglin Zhang; Enrico Faulhaber; Louis-Pierre Regnault; Deepak Singh; Pengcheng Dai

doi:10.1103/physrevb.84.024518

arXiv · 1105.4923

In-plane magnetic field effect on the neutron spin resonance in optimally doped FeSe$_{0.4}$Te$_{0.6}$ and BaFe$_{1.9}$Ni$_{0.1}$As$_{2}$ superconductors

Shiliang Li·Xingye Lu·Meng Wang·Hui-qian Luo·Miaoyin Wang·Chenglin Zhang·Enrico Faulhaber·Louis-Pierre Regnault·Deepak Singh·Pengcheng Dai

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Abstract

We use inelastic neutron scattering to study the effect of an in-plane magnetic field on the magnetic resonance in optimally doped superconductors FeSe$_{0.4}$Te$_{0.6}$ ($T_c=14$ K) and BaFe$_{1.9}$Ni$_{0.1}$As$_{2}$ ($T_c=20$ K). While the magnetic field up to 14.5 Tesla does not change the energy of the resonance, it particially suppresses $T_c$ and the corresponding superconductivity-induced intensity gain of the mode. However, we find no direct evidence for the field-induced spin-1 Zeeman splitting of the resonance. Therefore, it is still unclear if the resonance is the long-sought singlet-triplet excitation directly coupled to the superconducting electron Cooper pairs.

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Shiliang Li, Xingye Lu, Meng Wang, Hui-qian Luo, Miaoyin Wang, Chenglin Zhang, Enrico Faulhaber, Louis-Pierre Regnault, Deepak Singh, Pengcheng Dai. 2011-05-26. In-plane magnetic field effect on the neutron spin resonance in optimally doped FeSe$_{0.4}$Te$_{0.6}$ and BaFe$_{1.9}$Ni$_{0.1}$As$_{2}$ superconductors. https://doi.org/10.1103/physrevb.84.024518

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