Interstitial substitutions of vanadyl ions doped in single crystals of hexaimidazole cobalt sulphate: An EPR study

Abstract

Electron paramagnetic resonance studies on single crystals of hexaimidazole cobalt(II) sulphate doped with VO(II) are carried in the temperature range 77 -300 K at X-band frequencies. Single crystal EPR spectra indicate the presence of vanadyl impurity positioned in four sites with intensity ratios of 45 : 36 : 6 : 1. Angular variation studies in all the three orthogonal planes confirm that both the intense vanadyl sites have occupied interstitial positions in the lattice. The spin Hamiltonian parameters, calculated for the two sites, indicate orthorhombic nature for the impurity. However, the analysis of powder spectrum reveals the presence of only one site. The spin-lattice relaxation parameters have been calculated at various temperatures from line width measurements. The admixture coefficients have also been calculated.

Single-crystal EPR investigation of Mn(II)-doped biomineral cobalt ammonium phosphate hexahydrate: a case of multiple substitutions

“…However, the extra information, obtained from paramagnetic lattices that are EPR-active only at lower temperatures, are spin-lattice relaxation times, the nature of interaction between the guest and host ions, that are absent in diamagnetic host lattices. Many EPR studies of Mn(II), a high-spin d 5 [5][6][7][8][9]. The reason for this great interest is that the d 5 ion has no nearby crystal field states and thus EPR is easily detected over a large range of temperatures in any crystal field symmetry.…”