Dielectric behavior of paraelectric KTaO3, CaTiO3, and (Ln1/2Na1/2) TiO3 under a dc electric field -: art. no. 184104

The dc electric-field dependence of dielectric constant in the paraelectrics, KTaO3 single crystals, CaTiO3 and (Ln(1/2)Na(1/2))TiO3 (Ln = La and Nd) ceramics is studied at cryogenic temperatures in the dc electric-field range 0-60 kV/cm. The results indicate that KTaO3 possesses a high tunability K{=[epsilon (E-0)-epsilon (E)]/epsilon (E-0) = similar to 50%} at 20 kV/cm, and low dielectric loss tan delta (similar to0.003); while CaTiO3 and (Ln(1/2)Na(1/2))TiO3 (Ln = La and Nd) show low tunability of similar to1% and similar to0.1%, respectively, at 20 kV/cm; however, the dielectric loss tan delta is very small (similar to0.0004-0.003). The possible physical mechanism of the behavior observed is discussed.