EPR of lithium-sodium tetragermanate single crystal doped with copper ion

Abstract

For the first time electron paramagnetic resonance (EPR) spectra are studied in lithium-sodium tetragermanate (LiNaGe₄O₉) single crystal doped with copper impurity. The hyperfine quadruplets of two-valent Cu²⁺ ions (3d⁹, S =1/2, I = 3/2) are detected. The angular variations of the EPR spectra are studied in crystal planes at 295 K. The components of g-factor and hyperfine interaction tensor A are calculated. The EPR spectra anisotropy testifies the triclinic symmetry of the Cu²⁺ ions position in the lattice. The symmetry of the impurity site as well as the ratio of the ionic charges and radii give evidence that Cu²⁺ centers are substituted for Li⁺ ions in the LiNaGe₄O₉ crystal lattice. The charge imbalance of the dopant is presumably compensated by non-stoichiometric lithium ions vacancies.