Solid state reaction synthesis and optical spectroscopy of ferroelectric (Gd1−xLnx)2(MoO4)3; with Ln = Yb or Tm

A solid state synthesis route was used to prepare (Gd1−xLnx)2(MoO4)3, Ln = Yb or Tm, compounds with ferroelectric Pba2 crystal structure. It has been observed that this phase is the only one crystallized during 1123 K annealing for x ≤ 0.12 for Yb and x ≤ 0.3 for Tm. Above these concentration limits the simultaneous formation of trihydrated Ln2(MoO4)3, Ln = Yb or Tm, is observed. Up to these concentrations Yb and Tm incorporations do not degrade the SHG efficiency. The position of Yb3+ and Tm3+ energy levels involved in laser emission processes were determined by 5 K spectroscopy. The 300 K pumping and emission spectral distributions and excited level lifetime have been determined with the purpose of future applications as self-activated periodically poled ferroelectric laser and non-linear media.