Photodielectric effect in lead molybdate monocrystals

Illumination by light with photon energy near the band gap increases the dielectric permittivity of lead molybdate (PbMoO 4 ) crystals. This photodielectric effect (PDE) is observed at low measured frequencies (less than 10 kHz). A plot of dielectric permittivity against temperature has a wide maximum in the 470–500 K interval. The PDE essentially increases after exposure to sunlight or ultraviolet light. The PDE may be explained by the increase of polarizability of complex lattice defects by photoexcited electrons. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)