Heterometallic compounds containing lanthanides and transition metals, X2Cu(TeO3)2(SO4)2 (X = Eu, Gd, Sm, Tb,Tm, Y, and Yb), have been studied by magnetic susceptibility and variable frequency electron paramagnetic resonance (EPR). Single crystals of these novel compounds were synthesized by hydrothermal methods. The crystal structure of these isotypic compounds contains LnO8 polyhedra and CuO6 octahedra which are chelated by TeO32- and SO42- anions, forming a three-dimensional (3D) framework, as seen in Figure 1. Magnetic susceptibility measurements on polycrystalline samples reveal antiferromagnetic phase transition occurring at temperatures below 10 K in the Eu- and Tb-analogs. 34 GHz, powder EPR measured at 290K showed slightly asymmetric and broad single lines at g-values in the range 2.1 and 2.25, except in the Dy- and Tb- analogs which showed no signals. The Y-analog displayed a three-line spectrum typical of an S=1/2 system with rhombic symmetry, most likely due to the Cu2+ ions. Variable temperature, high field EPR measurements at 240 GHz and 336 GHz were conducted and yielded a wide variety of results for the various analogues. The high frequency EPR data sheds light on the magnetic structure and interactions exhibited by these compounds which go relatively undetected in low field EPR and magnetic susceptibility studies.

High field and high frequency EPR study of isotypic herterobimetallics

249th National Meeting (2015)

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