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Bistable Acoustic Delay Line

IP.com Disclosure Number: IPCOM000077056D
Original Publication Date: 1972-Jun-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Hoechli, UT: AUTHOR

Abstract

Ferroelastic insulators below their phase transition have two stable states with different elastic properties. They can be converted one into another by application of stress. If ferroelasticity is accompanied by ferroelectricity, conversion can also be achieved by application of an electrical field.

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Bistable Acoustic Delay Line

Ferroelastic insulators below their phase transition have two stable states with different elastic properties. They can be converted one into another by application of stress. If ferroelasticity is accompanied by ferroelectricity, conversion can also be achieved by application of an electrical field.

Gadolinium molybdate - Gd2(MoO4)3 - is a material which is both ferroelastic and ferroelectric at room temperature. Applying pressure of about 10 kg/cm/2/ is sufficient to effect switching. Longitudinally polarized sound shows the following properties in both stable states: State A State B

Sound velocity (m/sec) 3615 4065

Delay (Mu sec/cm) 2.77 2.46

Attenuation (db/cm) 0.2 0.2.

Quartz transducers are glued to the end faces of a slab of gadolinium molybdate and transmit sound along the x-axis. Condenser plates on a pair of lateral sides permits application of an electric field along z-axis to switch the material between both stable states.

Alternately, pressure can be applied to the other pair of lateral sides to induce a stress field in the slab for switching. Since either state causes a different and well-defined sound velocity, such an acoustic delay line is switchable between two different delays.

If it controls an oscillator, the latter is switched between two frequencies.

Gd2(MoO4)3 is also piezoelectric, thus transducers can be made to control the frequency of an RF transmitter. Thus, using the switching properties of this material,...