Disorder effects on the luminescence decay in yttria-stabilized zirconia polycrystals

Yellow - orange luminescence decay curves upon excitation in the intrinsic absorption region of polycrystalline tetragonal and cubic yttria-stabilized zirconia are reported and analysed on the basis of disorder effects. For all the samples the decay curves exhibited clearly non-trivial exponential forms strongly dependent of temperature which can be successfully fitted to an algebraic exponential law. This law is found to be common for relaxation processes in disordered systems. An attempt to elucidate the physical meaning of the algebraic parameters is made. The results are in good agreement with luminescence originated at F-type centres largely affected by the short-range disorder present in the samples.