Electron paramagnetic resonance of vanadyl ions in cadmium sodium phosphate hexahydrate single crystals: two locations for VO(II) Original Research Article

Electron paramagnetic resonance (EPR) studies of vanadyl ions, VO(II), as paramagnetic impurity in cadmium sodium phosphate hexahydrate (CdNaPO4·6H2O, CSPH) is studied at room temperature. The EPR analysis shows the presence of two magnetically different sites. The intense vanadyl ion has entered the lattice substitutionally and the other ion with weak intensity cannot be followed during the crystal rotations, but is clearly seen in the powder spectra indicating that they are chemically inequivalent in nature. The spin-Hamiltonian parameters obtained from the single crystal analysis have matched with the values of site-I of powder spectra, the values being: g∥=1.922 g⊥=1.980, The spin-Hamiltonian parameters evaluated from powder EPR data are: Site I: g∥=1.922; g⊥=1.995, Site II: g∥=1.933; g⊥=1.996, The admixture coefficients have matched fairly well with reported values.