Acoustic waves in micropolar elastic ferroelectrics

• We use a new approach where polarization depends on macro and micro-deformations.
• Consequences of dipole, quadrupole and electric field on acoustic modes are new.
• Coupling of modes are easily described adopting a simple micropolar model.
• Attenuation and frequency cutoff are shown to depend on the electric field.

A recent electro-magneto-elastic extension of microcontinuum elasticity is exploited to estimate the consequences of electro-elastic interactions, due to intrinsic polarization in ferroelectrics, on the propagation of acoustic modes. The model is applied and compared to a micromechanical analysis of perovskite-like structures developed in the past and reducible to a micropolar continuum model. Qualitative and quantitative effects due to electric dipole and quadrupole densities are discussed concerning phase speeds, cutoff frequencies and attenuation.