Photoinduced permittivity in lead molybdate

The effect of illumination on the dielectric properties of lead molybdate (PbMoO₄) single crystals was studied. Illumination with intrinsic light gives rise to a substantial enhancement of low-frequency permittivity (the photodielectric effect, PDE). The PDE is dependent on temperature and reaches a maximum near 400 K. The permittivity reaches the steady state a long time after the light is turned on (off). The relaxation time and activation energy of the process were determined. The relation of the PDE to the photoconductivity of the crystal is discussed. A possible mechanism of the PDE in PbMoO₄ crystals is proposed.