Doped alkaline–bismuth–titanate perovskite single crystals have been grown in ferroelectric phases with high piezoelectric actuation. Rhombohedral-phaseNa1/2Bi1/2TiO3–BaTiO3crystals exhibit up to 0.25&percent; free strain with low hysteresis along the cubic ⟨001⟩ direction(d33∼450 pC/N).Tetragonal phase crystals exhibit free strains as high as 0.85&percent; with greater hysteresis characteristic of domain switching; low fieldd33exceeds 500 pC/N. Strain energy densities exceed those of optimized polycrystalline lead perovskites, and actuation capability is retained at compressive stresses >100 MPa. ©1998 American Institute of Physics.