EPR and Magnetic Susceptibility Studies on the Structure and Polaron Dynamics on V_2O_5-, MoO_3- and CuO-Containing Glasses

摘要

EPR lineshapes studies on 0.7V_2O_5-0.3P_2O_5 (S1), 0.7MoO_3-0.2B_2O_3 (S2), 0.5MoO_3-0.2Sb_2O_3-0.3K_2O (S3), and 0.05CuO-0.7B_2O_3-0.25Li_2O (S4) glasses were performed at various temperatures. The trends in g-values of g_‖ < g⊥ in the cases of S1, S2 and gx < g_‖ in S3 and S4 show that the paramagnetic ions formed in the matrices are vanadyl, VO~(2+), molybdenyl, MoO~(3+), Mo~(5+) and Cu~(2+), respectively in highly distorted octahedra of oxygens having C_(4v) symmetry. The values of the small polaron exchange integrals calculated from the magnetic susceptibility data at 300 K are found to be 0.04, 0.012, 0.004, and 0.028 eV for S1, S2, S3, and S4, respectively. However, exchange integrals calculated from the non-linear fit of the magnetic susceptibility versus temperature plots of S3 and S4 in the range 4.2-300 K are found to be 0.001 eV in both the glasses.