A relaxor ferroelectric single crystal cut resulting in large d ₃₁₂ and zero d ₃₁₁ for a shear mode accelerometer and related applications

Relaxor ferroelectric single crystals exhibit anisotropic piezoelectric behavior. This enables the use of a combination of crystal cut and poling to obtain piezoelectric properties optimized for certain applications. This work describes a crystal cut that is optimized for applications where a strong face shear mode d ₃₁₂ coupling is desired with a zero d ₃₁₁ or zero d ₃₂₂ piezoelectric coefficient. Such a crystal cut enables the production of stack actuators in a long bar shape with the electric field perpendicular to the bar length. These bars can be cantilevered with a mass at the end to produce a highly sensitive shear mode accelerometer. The zero value of d ₃₁₁ or d ₃₂₂ eliminates a possible extensional mode coupling along the length of the bar. Only one of d ₃₁₁ or d ₃₂₂ can be made equal to zero, the other having a negative value.