199 research outputs found
Effect of magnetic field on the spin resonance in FeTe(0.5)Se(0.5) as seen via inelastic neutron scattering
Inelastic neutron scattering and susceptibility measurements have been
performed on the optimally-doped Fe-based superconductor FeTe(0.5)Se(0.5),
which has a critical temperature, Tc of 14 K. The magnetic scattering at the
stripe antiferromagnetic wave-vector Q = (0.5,0.5) exhibits a "resonance" at ~
6 meV, where the scattering intensity increases abruptly when cooled below Tc.
In a 7-T magnetic field parallel to the a-b plane, Tc is slightly reduced to ~
12 K, based on susceptibility measurements. The resonance in the neutron
scattering measurements is also affected by the field. The resonance intensity
under field cooling starts to rise at a lower temperature ~ 12 K, and the low
temperature intensity is also reduced from the zero-field value. Our results
provide clear evidence for the intimate relationship between superconductivity
and the resonance measured in magnetic excitations of Fe-based superconductors.Comment: 4 pages, 3 figure
Direct observation of magnon-phonon coupling in yttrium iron garnet
The magnetic insulator yttrium iron garnet (YIG) with a ferrimagnetic
transition temperature of 560 K has been widely used in microwave and
spintronic devices. Anomalous features in the spin Seeback effect (SSE)
voltages have been observed in Pt/YIG and attributed to the magnon-phonon
coupling. Here we use inelastic neutron scattering to map out low-energy spin
waves and acoustic phonons of YIG at 100 K as a function of increasing magnetic
field. By comparing the zero and 9.1 T data, we find that instead of splitting
and opening up gaps at the spin wave and acoustic phonon dispersion
intersecting points, magnon-phonon coupling in YIG enhances the hybridized
scattering intensity. These results are different from expectations of
conventional spin-lattice coupling, calling for new paradigms to understand the
scattering process of magnon-phonon interactions and the resulting
magnon-polarons.Comment: 5 pages, 4 figures, PRB in pres
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