Published online by Cambridge University Press: 15 February 2011
Results of iron-5 7 Mössbauer spectroscopy and ac and dc susceptibility study of the double perovskite phases, CaFeTi2O6 (A) and CaFe3Ti4O12 (B) are presented. Both phases exhibit spectral broadening effects with decreasing temperature and incipient magnetic hyperfine splitting attributable to novel slow paramagnetic relaxation at the tetrahedral and square planar sites of (A) and the square planar sites of (B). The temperature dependence of magnetic moment for (A) corresponds to classical single ion zero field splitting, while that of (B) indicates antiferromagnetic exchange interactions. There is no evidence of cooperative long range magnetic order in these materials.