An electron paramagnetic resonance study of vanadium centres in RbZnF3 single crystals

• Published in: Journal of physics. Condensed matter Vol. 20; no. 5; pp. 055221 - 055221 (7)
• Main Authors: Takeuchi, H, Ebisu, H, Arakawa, M
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 06.02.2008; Institute of Physics
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron paramagnetic resonance and relaxation; Exact sciences and technology; Magnetic resonances and relaxations in condensed matter, mössbauer effect; Physics; Complex defect; Cubic lattices; Perovskites; High temperature; Impurity pair; Vanadium additions; Hyperfine structure; Hexagonal lattices; Monocrystals; Angular variation; Electron paramagnetic resonance; Codoping; Lithium additions
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/20/5/055221

Electron paramagnetic resonance (EPR) measurements have been made at room temperatures for sample crystals of RbZnF3 doped only with vanadium and codoped with vanadium and lithium. For the V-only-doped crystal, two kinds of EPR spectra having eight-line hyperfine structure () were observed. One spectrum with cubic symmetry is ascribed to a V2+ ion () substituting for a host Zn2+ ion. The other spectrum with tetragonal symmetry is ascribed to a V4+-O2- pair () substituting for the host Zn2+-F- pair in the cubic perovskite phase of the matrix crystal. In the V, Li-codoped crystal, two kinds of new EPR spectra having monoclinic symmetry with and were observed, and no V2+ centres were observed. The new spectra are ascribed to VLiOF8 complexes formed at Zn2F9 units in the hexagonal BaTiO3 type phase of the matrix crystal. In these centres, excess divalent positive charges on the V4+ ions are compensated justly by forming V4+-Li+-O2- structures. It is confirmed from the results that the hexagonal BaTiO3 type high temperature phase of RbZnF3 can be stabilized even in the temperature region of the cubic perovskite type phase of pure RbZnF3 crystal by the preferential formation of V4+-Li+ pairs at the hexagonal Zn2F9 units.