MAGNETIC INTERACTIONS OF CERIUM AND COBALT IONS IN DOUBLE NITRATE CRYSTALS. Technical Report No. 2

The space group of the double nitrate crystals M(?)M(?) (NO/sub 3/)/sub 12/- 24H/sub 2/O where M is a trivalent cation and M" is a divalent cation has been determined from x-ray data to be R3m. The rhombohedral unit cell has sides of 13.9 A and interaxial angles of 49', and it contains one molecule. The cerium ions have the location plus or minus (1/4, 1/4, 1/4). The line shapes of the derivative of paramagnetic-resonance absorption of small concentrations of cobaltous ions substituted in Ce/sub 2/ Zn/sub 3/ (NO/sub 3/)/sub 12/ (?) 24H/sub 2/0 are described and used to determine the spatial relations of the cerium ions and cobalt ions, as well as to justify the assumption of a dipolar interaction between them described by the spin Hamiltonian parameters of the cerium and cobalt ions. It is concluded that the more isotropic of the two paramagnetic spectra of cobalt ions obsered in this salt is due to ions in either the special sites plus or minus (0-399, 0-399, 0-399) or, less likely, in the special sites plus or minus (0-101, 0-101, 0-101) and that the highly anisotropic spectra of cobalt ions is due to ions in the body-centered site. (auth)