{"id":650,"date":"2022-01-08T16:53:44","date_gmt":"2022-01-08T13:53:44","guid":{"rendered":"https:\/\/labsensors.org\/?page_id=650"},"modified":"2022-01-08T17:21:31","modified_gmt":"2022-01-08T14:21:31","slug":"proekt-19-07-00070","status":"publish","type":"page","link":"https:\/\/labsensors.org\/en\/reports\/proekt-19-07-00070\/","title":{"rendered":"Project &#8220;Backward acoustic waves in multilayered structures based on piezoelectrics and piezosemiconductors&#8221;"},"content":{"rendered":"<p><strong>Project 19-07-00070 &#8220;Backward acoustic waves in multilayered structures based on piezoelectrics<br \/>\nand piezosemiconductors<\/strong><strong>&#8220;<\/strong><\/p>\n<p>Backward acoustic waves are characterized by oppositely directed phase and group velocities. In<br \/>\nrecent years, these waves have attracted the attention of researchers in connection with the<br \/>\nimplementation of a new type of acoustic sensors or signal processing devices on their basis. The<br \/>\naim of this project was a theoretical and experimental study of the features of the excitation and<br \/>\npropagation of backward acoustic waves in piezoelectric and piezosemiconductor materials and<br \/>\nstructures under various boundary conditions and in contact with a liquid. To achieve this goal,<br \/>\nthe following tasks were solved: i) a theoretical analysis of the features of propagation of<br \/>\nbackward waves in piezoelectric semiconductor plates under various boundary conditions was<br \/>\ncarried out and ii) an experimental study of the effect of liquid and conducting layers on the<br \/>\nproperties of backward waves in piezoelectric plates was carried out. As a result of the project,<br \/>\nthe frequency ranges were discovered for the first time in which there is a reverse antisymmetric<br \/>\nwave of the 1st order (A1) and a symmetric wave of the 2nd order (S2), propagating in the [001]<br \/>\ndirection in the (110) plane of GaAs. Analysis of the effect of a layer with arbitrary conductivity,<br \/>\nplaced on the surface of the GaAs plate, on the characteristics of the detected backward acoustic<br \/>\nwaves A1 and S2 showed that their attenuation decreased with increasing surface conductivity.<br \/>\nWhile their phase velocity remained practically unchanged. In addition to backward waves in<br \/>\npiezoelectric semiconductor plates, the influence of various boundary conditions on the<br \/>\nproperties of the previously detected backward wave A1 in the YX plate of lithium niobate was<br \/>\nstudied. It was shown that in the case of contact of the plate under consideration with a residual<br \/>\nand non-conducting liquid, the amplitude of forward waves with transverse-horizontal<br \/>\npolarization increases, and in the case of antisymmetric waves, both forward and backward, their<br \/>\namplitude decreases significantly. The main conclusions of the theory were confirmed<br \/>\nexperimentally. We also studied the A1 backward wave in the structure &#8220;lithium niobate YX<br \/>\nplate &#8211; vacuum gap &#8211; metal plane&#8221;. It was shown that approaching the metal plane to the<br \/>\npiezoelectric plate leads to an increase in the phase velocity of the wave under consideration. At<br \/>\nthe same time, the phase velocity of the forward A1 wave &#8211; decreased. In addition, it was found<br \/>\nthat the approximation of the metal plane leads to a change in the distribution of the amplitudes<br \/>\nof mechanical displacement over the thickness of the plate, and the electric potential of the wave<br \/>\nin the plate decreases relative to the potential on the surface. In general, the results obtained<br \/>\nallowed a deeper understanding of the features of propagation of backward acoustic waves in<br \/>\npiezoelectric semiconductor plates and structures with a gap.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Project 19-07-00070 &#8220;Backward acoustic waves in multilayered structures based on piezoelectrics and piezosemiconductors&#8220; Backward acoustic waves are characterized by oppositely directed phase and group velocities. In recent years, these waves have attracted the attention of researchers in connection with the implementation of a new type of acoustic sensors or signal processing devices on their basis. [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":538,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-650","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/labsensors.org\/en\/wp-json\/wp\/v2\/pages\/650","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/labsensors.org\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/labsensors.org\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/labsensors.org\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/labsensors.org\/en\/wp-json\/wp\/v2\/comments?post=650"}],"version-history":[{"count":2,"href":"https:\/\/labsensors.org\/en\/wp-json\/wp\/v2\/pages\/650\/revisions"}],"predecessor-version":[{"id":665,"href":"https:\/\/labsensors.org\/en\/wp-json\/wp\/v2\/pages\/650\/revisions\/665"}],"up":[{"embeddable":true,"href":"https:\/\/labsensors.org\/en\/wp-json\/wp\/v2\/pages\/538"}],"wp:attachment":[{"href":"https:\/\/labsensors.org\/en\/wp-json\/wp\/v2\/media?parent=650"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}