Effect of Cr and Mn doping on ferroelectric and dielectric properties of Li_1.72Na_0.28Ge₄O₉single crystals

Optical absorption of LiNaGe4O9:Mn crystal

“…Hence, charge perturbation and structural deformations accompanying Mn 4+  Ge 4+ substitution can be assumed as unessential. Just the absence of charge and mechanical disturbances explains the zero doping effect on the PT temperature in LNG:Mn crystal [5]. In contrast, strong influence of doping on the PT point in LNG:Cr crystal can be associated with significant local disturbance of the structure induced by Cr 3+ -ALi pair dipolar centers which were discussed earlier in [9 -10].…”

“…One can expect that doping with transition ions should significantly modify the properties of LG4 and LNG crystals. For example, recently it was shown that doping Li2-хNaxGe4O9 crystals (х = 0.28) with Cr ions shifted the temperature ТC of the ferroelectric phase transition from 257 to 267 K, while doping with Mn ions practically did not change ТC [5]. The authors of [6] studied optical and EPR spectra and concluded that chromium ions in trivalent charge state Cr 3+ substituted for Ge 4+ host ions in the LNG crystal lattice.…”

Combinatorial synthesis and screening of (Ba,Sr)(Ti,Mn)O3 thin films for optimization of tunable co-planar waveguides

“…Generally however, doping on the B site of titanate-based perovskite films is carried out with variable valence elements such as Fe, Co, Mn and Cr. These transition metal ions compensate for native levels of VO .. but equally can exist in higher valence (iii and iv) states according to the following [26][27][28] AO1.5  ATi'…”