The 181Hf/181Ta Probe in the Li and Nb Sites of Congruent LiNbO3 Co-doped with Mg and Cr Ions Studied by γ-γ PAC

Lattice location of Hf and its interaction with other impurities in LiNbO3: a review

“…12 Fraction of Hf found occupying Nb sites as function of the Hf content in congruent LiNbO 3 . Drawn using data from Rebouta et al, 27 Marques et al, 77 and Dias et al 78 The solid line results from the application of the incorporation model of Marques et al 77 Optical Engineering 060901-8 June 2014 • Vol. 53 (6) both Li and Nb sites, depending on stoichiometry and codopants has led to a good understanding of the conditions that define its location.…”

“…17 Minzioni et al have suggested that the threshold is connected with the occupation of Nb sites by Hf. 17 However, our data have shown that Hf starts occupying Nb sites well below 2 mol% doping, 78 suggesting that the threshold at 3 to 4 mol% is rather linked to the dissolution of the intrinsic stacking inversions, 39 which must happen subsequently to the dissolution of the Nb antisites.…”

“…76 Crystals codoped with 2 and 3 mol% HfO 2 plus 0.1 mol% Cr 2 O 3 were also studied using PAC. 78 The Hf probes were found occupying both Nb and Li sites in these crystals. It was necessary to consider a frequency doublet for probes in Li sites, ν Q ðLi IÞ and ν Q ðLi IIÞ, as in the case of the congruent crystal doped with 1 mol% HfO 2 , but unlike the crystal doped with 6 mol% HfO 2 .…”