BRAGG SOUND REFLECTION IN PIEZOCRYSTAL SU PERCONDUCTING OR METALLIZEDMULTILAYERS

The transverse elastic wave reflection from piezomagnetic/thin superco nducting multilayers and from piezoelectric/metallized interface multi layers is studied. The conditions are analyzed for the Bragg resonance for which within the spectral intervals narrow on the scale of smalln ess of the magneto- or electromechanical coupling parameters q2 the re flectivity is close to a unit. The effect of resonance reflection ampl ification manifests drastically in the multilayers formed by the layer s of the same materials, since in this situation the reflectivity far from the resonance region of frequencies (or incident angles) has the order of the magnitude q2. In addition, for the case of piezomagnetic layered structure with the transition of interlayer coatings into n-st ate the reflection vanishes nearly, i.e., the reflectivity may change by jump from zero to values close to a unit due to the variation of th e phase state of superconducting layers, e.g., by means of temperature or electric current.