Investigation of the [l,0,0] polarization of iron-doped barium titanate under irradiation

In this first paper an investigation of the pyroelectric effect is performed on iron-doped barium titanate (and also on cobalt-doped barium titanate) in the [1, 0, 0] direction, and during both continuous and limited irradiation.The results obtained reveal an alteration of both the ferroelectric and paraelectric properties, characterized especially by a polydomainization (appearance of a diffuse phase transition (T < Tc)) and by an unusual electrical discharge (T > Tc).The results indicate that a new coupling between anharmonic properties and electrons must be introduced, during and after a photoelectric active irradiation. This point will be developed in the following paper.