CONSTRUCTION OF A VERNIER TANDEM (3+3)-PASS BRILLOUIN SPECTROMETER AND ITS APPLICATION TO SURFACE-ACOUSTIC-WAVE STUDY IN METALLIC MULTILAYER FILMS

In order to study the elastic and magnetic properties of metallic multilayers by Brillouin scattering, we have constructed a (3+3)-pass vernier tandem Fabry-Perot interferometer. We have also developed master/slave and time-sharing techniques and electronics,to stabilize the interferometer during a long spectrum accumulation period of over several hours. In this report, we describe the details of the tandem spectrometer and the control techniques. As an application of the tandem spectrometer, we have studied sound velocity of Rayleigh surface waves existing in Ag/Cu multilayers as a function of the multilayer period. We have observed considerable softening of more than 20% of the surface velocity as the multilayer period decreases from 150 angstrom to 7 angstrom.