Electron Paramagnetic Resonance of Several Rare-Earth Impurities in the Cubic Perovskite KMgF3

EPR and optical spectroscopy of neodymium ions in KMgF3 and KZnF3 crystals

“…In case of KZnF3:Nd 3+ (III) Nd 3+ most probably substitutes Mg 2+ and the compensation is provided by the vacancy in the location of K § In this case the crystal field is more sensitive to the vacancy than when the substitution of K § and vacancy in the location of Mg 2+ occur. Our supposition is supported by structural models of tfigonal Dy 3 § Er 3 § and Yb 3+ centers in KMgF 3 [15,16]. For BaTiO3:Nd 3+ it follows flora our considerations that Nd 3+ subsfitutes Ba 2 § This conclusion agrees with the structural model proposed in [3].…”

Investigations on the local structures of the two trigonal Er3+ centers in KMgF3

“…Additionally, the difference between the experimental g factors for centers I and II may originate from the different occupation (on Mg 2+ or K + site) and the dissimilar axial shifts ∆Z L of Er 3+ in both centers. Moreover, it can be expected that the large displacement of Er 3+ is responsible for the significant anisotropy of the observed g factors for each center [12]. Recently, similar considerable g anisotropies were also reported in some interesting and systematic work on the low-symmetry (tetragonal or orthorhombic) Er 3+ (and other trivalent rare earth ions) centers in various crystals [29 -32].…”

“…This tetragonal center was attributed to Er 3+ occupying the Mg 2+ site with one substitutional O 2-ion at the original nearest F -site along the [100] direction due to charge compensation [12]. In view of the tetragonal symmetry of this center, quantitative studies of its g factors need to involve different theoretical models (or perturbation formulas) and probably different physical mechanisms from those for the trigonal centers considered in the present work.…”

“…167 Er with nuclear spin I = 7/2) centers I and II in KMgF 3 in EPR experiment at 1.5 K [12]. According to the authors, center I was attributed to the Er 3+ impurity occupying the octahedral Mg 2+ site, associated with one K + vacancy V K along the C 3 axis due to charge compensation, while center II was supposed as the Er 3+ residing in the dodecahedral K + site, associated with one Mg 2+ vacancy V Mg along the C 3 axis due to charge compensation [12]. Up to now, however, these assignments for the two trigonal Er 3+ centers have not been theoretically verified, and the local structures of both centers have not been determined either.…”

Electron nuclear double resonance of the cubic Dy3+ center in the KZnF3 single crystal

“…1 where the hyperfine structure components of the 161 Dy3 + and 163Dy3+ isotopes are also marked. The EPR parameters of the studied center and the analogous data for KMgF 3 (from [9]) are given in Table 1. The ENDOR experiments were for the most part carried out on the even Dy 3 + isotope.…”