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Titolo:
Incredible negative values of effective electromechanical coupling coefficient for surface acoustic waves in piezoelectrics
Autore:
Mozhaev, VG; Weihnacht, M;
Indirizzi:
Zent Inst Festkorperphys & Werkstofforsch, D-01069 Dresden, Germany Zent Inst Festkorperphys & Werkstofforsch Dresden Germany D-01069 ermany Moscow MV Lomonosov State Univ, Fac Phys, Moscow 117234, Russia Moscow MV Lomonosov State Univ Moscow Russia 117234 oscow 117234, Russia
Titolo Testata:
ULTRASONICS
fascicolo: 10, volume: 37, anno: 2000,
pagine: 687 - 691
SICI:
0041-624X(200007)37:10<687:INVOEE>2.0.ZU;2-L
Fonte:
ISI
Lingua:
ENG
Soggetto:
KNBO3;
Keywords:
surface acoustic waves; potassium niobate; electromechanical coupling coefficient; Rayleigh wave; Bleustein-Gulyaev wave;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Engineering, Computing & Technology
Citazioni:
10
Recensione:
Indirizzi per estratti:
Indirizzo: Weihnacht, M Zent Inst Festkorperphys & Werkstofforsch, Helmsholtzstr 20, D-01069 Dresden, Germany Zent Inst Festkorperphys & Werkstofforsch Helmsholtzstr 20 Dresden Germany D-01069
Citazione:
V.G. Mozhaev e M. Weihnacht, "Incredible negative values of effective electromechanical coupling coefficient for surface acoustic waves in piezoelectrics", ULTRASONICS, 37(10), 2000, pp. 687-691

Abstract

The extraordinary case of increase in velocity of surface acoustic waves (SAW) caused by electrical shorting of the surface of the superstrong piezoelectric crystal potassium niobate, KNbO3, is numerically found. The explanation of this effect is based on considering SAWs as coupled Rayleigh and Bleustein-Gulyaev modes. A general procedure of approximate decoupling of themodes is suggested for piezoelectric crystals of arbitrary anisotropy. Theeffect under study takes place when the phase velocity of uncoupled sagittally polarized Rayleigh waves is intermediate between the phase velocities of uncoupled shear-horizontal Bleustein-Gulyaev waves at the free and metallized surfaces. In this case, the metallization of the surface by an infinitely thin layer may cause a crossover of the velocity curves of the uncoupled waves. The presence of the mode coupling results in splitting of the curves with transition from one uncoupled branch to the other. This transitionis responsible for the increase in SAW velocity, which appears to be greater than its common decrease produced by electrical shorting of the substrate surface. (C) 2000 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/12/20 alle ore 09:36:52