Abstract :
Quasi-longitudinal (QL) Anisimkin Jr.´ modes discovered recently in quartz plates are found now in 2 other piezoelectric crystals, belonging to trigonal symmetry. In 128degY,X+90deg-LiNbO3, 2 different QL modes may propagate simultaneously for small plate thickness h/lambda = 0 to 0.06 (h is thickness, lambda is wavelength). The velocity of the 1st mode, v1, is close to the longitudinal bulk wave velocity vL. It is varied with h/lambda and piezoelectrically stiffened (maximum Kn 2 = 39% at h/lambda = 0.08). The velocity of the 2nd QL mode, v2, is close to the shear-horizontal bulk wave velocity vQSH, not varied with h/lambda and not stiffened (Kn 2 = 0). On the contrary, 210degY,X-Te crystal supports only one QL-mode, but it is unusually wideranging and low-dispersive: the mode exists for all h/lambda from 0 to 2.5 with velocity vn almost permanent and equal to vL in the whole range. This mode is piezoelectrically stiffened (maximum Kn 2 = 2% at h/lambda = 0.13). The variety of the Anisimkin Jr.´ modes in different crystals makes them attractive for liquid sensors, where the amount of suitable waves is very restricted.
Keywords :
acoustic wave velocity; bulk acoustic wave devices; lithium compounds; phonons; piezoelectric materials; quartz; tellurium; LiNbO3; Te; liquid sensors; longitudinal bulk wave velocity; piezoelectric crystals; piezoelectrical stiffening; quartz plates; shear-horizontal bulk wave velocity; small plate thickness; suasi-longitudinal Anisimkin Jr. plate modes; trigonal symmetry; Crystals; Metallization; Surface acoustic waves; Tellurium;
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on