EPR study of Mn(II)-doped CoH 6CeMo 12O 42·12H 2O: Host site symmetry and spin-lattice relaxation time

Abstract

Single crystal EPR studies of Mn(II)-doped cobalt 12-molybdocerate(IV) is studied at 300 K. The paramagnetic impurity is found to occupy the substitutional site of the cobalt atom. Angular variation of fine-structure lines shows the presence of a single site. The spin Hamiltonian parameters obtained at 300 K are D=224, E=−37, g ‖=2.013, g ⊥=2.003, A ‖=−81.5 and A ⊥=−76.7 ( A, D and E are in the units of 10 −4 cm −1). A large value of E is indicative of low symmetry for the substitutional site, in accordance with the crystal structure of the isomorphous CuH 6UMo 12O 42·12H 2O. From the line width of the dopant Mn(II), the T 1 of Co 2+ is estimated to be 2.6×10 −12 s at 300 K. The covalency of the Mn–O bond, estimated from Matamura’s plot, is 10.2%.