A 20 MHZ SINGLE-ELEMENT ULTRASONIC PROBE USING 0.91PB(ZN1 3NB2/3)O-3-0.09PBTIO(3) SINGLE-CRYSTAL/

A 20 MHz single-element ultrasonic probe using 0.91Pb(Zn1/3Nb2/3)O-3-0 .09PbTiO(3) (PZN-PT 91/9) single crystal has been fabricated. The sing le crystal of PZN-PT 91/9 orientated to the (001) plane has longitudin al coupling factor of k(33) > 90%, which is much larger than the k(33) = 70 to 80% of conventional Pb(Zr1-xTix)O-3 (PZT) based ceramics. A s ingle crystal of PZN-PT 91/9 without inclusion or crack has been grown with dimensions of about 25 x 15 x 5 mm by the self-flux method. Beca use mechanical strength in the fabrication of disk transducers orienta ted to the (001) plane was sufficiently strong, under the same conditi ons as are applied to conventional PZT ceramics, a piston single-eleme nt probe with a diameter of 2.0 mm and a frequency of 20 MHz was succe ssfully fabricated. The bandwidth of the PZN-PT 91/9 probe was 13-26 M Hz, which was 4 MHz broader than that of the conventional PZT probe.