Light Scattering from Bulk and Surface Spin Waves in EuO

Abstract

Our NMR experiments confirm the above conclusion. After a sample is quenched the NMR frequencies show time dependencies divided into the same two domains. Moreover, as shown in Fig. 2, we observe strikingly different coexistence curves and critical isochores in our quenched and nonquenched experiments. In the nonquenched experiment long waiting times (over twelve hours) occur before any measurement is made near T^. This insures that the xenon sample has come to equilibrium with the gravitational field. In the quenched experiment all measurements are made after a relatively short time, about 20-30 min following the quench. This time must be long enough to insure equilibrium between the liquid and vapor phases but short enough to insure minimal effects from gravitational gradients. As shown in Fig. 2 the quenching technique eliminates both the excess line broadening and the anomaly of two apparently separate signals (highdensity gas near bottom of sample and low-density vapor near top of sample) which occurs well above T^ in our nonquenched experiments as a result of the warped (sigmoid) gravitational density profile.We wish to acknowledge many helpful discussions with Joseph Sak concerning critical phenomena and with Gary S. Collins concerning computer programs.We present results of light-scattering experiments on thermal acoustic spin waves in EuO. The Brillouin spectra show two peaks which can be shifted by an external magnetic field. One of these is identified as due to a modified bulk spin wave of the material. The other one, by its anomalous behavior on reversal of the magnetic field or change of the scattering geometry, reveals itself as a spin wave propagating along the surface of the crystal.

Triple-Resonant Brillouin Light Scattering in Magneto-Optical Cavities

“…Asymmetries in magnon BLS have been reported previously due to other mechanisms. Localization of surface magnon modes with a given chirality [31] is not relevant here, as we study the uniform magnetic mode, and spin-spin correlations between different components introduced by the demagnetizing field are only relevant in a thin film geometry [32]. It is possible that interference between the first-(Faraday) and second-order (Voigt) magneto-optical effects [16,33] may result in minor corrections to the differing amplitudes.…”

Generating wave vector specific Damon-Eshbach spin waves in Py using a diffraction grating

“…Early experiments confirming the presence of these modes in slabs were typically performed using Brillouin light scattering (BLS) techniques. 4,5 Magnetostatic modes are of crucial importance in the growing field of magnonics. Strictly speaking, magnonics is analogous to electronics; magnonics is concerned with the transmission and processing of information via magnons (quantized spin waves) as opposed to electrons.…”

Standing Spin Waves Observed by Brillouin Scattering in Amorphous MetallicFe80B20Grimsditch1, Malozemoff2, Brunsch3 1979Phys. Rev. Lett.841200View full textAdd to dashboardCite

“…The peak labeled SM is the Stokes surface magnon (the absence of anti-Stokes is explained in the literature). 1 ' 2 The other peaks are the substructure of the bulk magnons, which interest us here. S and A refer to Stokes and anti-Stokes, respectively, and the subscript labels the successive lines.…”