Spin-wave excitations and superconducting resonant mode in Cs&lt;sub&gt;&lt;em&gt;x&lt;/em&gt;&lt;/sub&gt;Fe&lt;sub&gt;2-&lt;em&gt;y&lt;/em&gt;&lt;/sub&gt;Se&lt;sub&gt;2&lt;/sub&gt;

Taylor, A.E.; Ewings, R.A.; Perring, T.G.; White, J.S.; Babkevich, P.; Krzton-Maziopa, A.; Pomjakushina, E.; Conder, K.; Boothroyd, A.T.

doi:10.1103/PhysRevB.86.094528

Spin-wave excitations and superconducting resonant mode in Cs_xFe_2-ySe₂

Taylor AE, Ewings RA, Perring TG, White JS, Babkevich P, Krzton-Maziopa A, Pomjakushina E, Conder K & Boothroyd AT

Citation

Taylor, A. E., Ewings, R. A., Perring, T. G., White, J. S., Babkevich, P., Krzton-Maziopa, A., … Boothroyd, A. T. (2012). Spin-wave excitations and superconducting resonant mode in Cs_xFe_2-ySe₂. Physical Review B, 86(9), 094528 (7 pp.). https://doi.org/10.1103/PhysRevB.86.094528

Persistent URL https://www.dora.lib4ri.ch/psi/islandora/object/psi:12604

We report neutron inelastic scattering measurements on the normal and superconducting states of single-crystalline Cs_0.8Fe_1.9Se₂. Consistent with previous measurements on Rb_xFe_2-_ySe₂, we observe two distinct spin excitation signals: (i) spin-wave excitations characteristic of the block antiferromagnetic order found in insulating A_xFe_2-ySe₂ compounds, and (ii) a resonance-like magnetic peak localized in energy at 11 meV and at an in-plane wave-vector of (0.25,0.5). The resonance peak increases below T_c= 27 K, and has a similar absolute intensity to the resonance peaks observed in other Fe-based superconductors. The existence of a magnetic resonance in the spectrum of Rb_xFe_2-ySe₂ and now of Cs_xFe_2-ySe₂ suggests that this is a common feature of superconductivity in this family. The low-energy spin-wave excitations in Cs_0.8Fe_1.9Se₂ show no measurable response to superconductivity, consistent with the notion of spatially separate magnetic and superconducting phases.