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Dielectric spectra of ceramic samples of Ca1−xPbxTiO3 (0⩽x⩽0.4) solid solutions were studied at frequencies between 10 Hz and 1 MHz in a temperature range of 4.2–300 K. A ferroelectric phase transition was observed at x=0.3 with transformation to a relaxor type behavior at x>0.3. The transition temperature Tc follows a linear dependence Tc∝(x−xc) with xc=0.28 contrary to a square-root dependence Tc∝(x−xc)1/2 predicted by the theory for incipient ferroelectrics. The critical concentration essentially exceeds the xc values for SrTiO3 and KTaO3 incipient ferroelectrics.

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Interface acoustic waves at the (001) boundary of twisted single-crystal silicon wafers are studied using analytical and numerical techniques. A secular equation of the problem in an explicit form is derived for the propagation directions along the twist-angle bisectrix and a complete numerical solution is calculated for arbitrary propagation. A new mode of leaky-wave type is predicted. This leaky mode has a low propagation loss and distinct near-interface localization at small twist angles. The leaky wave is purely longitudinal at the interface in the bisectric case. A mode without leakage is found only in the vicinity of the bisectrix directions. Its feature is a rotating movement of interface particles in the plane normal to the propagation direction in the bisectrix case. The sector of azimuthal angles permitted for the propagation of the nonleaky mode has an unusual jumplike behavior as a function of the twist angle.

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