Magnetic properties of two copper (II)-halide layered perovskites

Abstract

The magnetic properties of the powdered layered structures of 3-ammoniumpyridinium tetrabromocuprate(II) and 3-ammoniumpyridinium tetrachlorocuprate(II) have been studied from 4.2 to 150 K. The data were interpreted using both 1D and 2D series expansions for the Heisenberg model, combined with the appropriate mean-field corrections, yielding interlayer exchanges with J2h/k values of (−11±2) K for the chloride salt and (−52±7) K for the bromide salt. The intralayer exchange (J1h/k) values were found to be (14±2) K and (20±2.5) K for the chloride and bromide salts, respectively. The new results are compared with previous results for the eclipsed layered structure series NH3(CH2)nNH3CuX4, where X=Br or Cl and n=2, 3, 4, or 5. As the halide-halide separation distance decreases the transition from magnetic isolation of the layers to a strong interlayer exchange is observed. The new study allows confirmation of the power dependence on the halide-halide separation.