Structural and magnetic investigation of Fe3+ and Mg2+ substitution into the trigonal bipyramidal site of InGaCuO4

The solid solutions of InGa1−xFexCuO4, InFeCu1−xMgxO4, and InGa1−xFexCu1−xMgxO4 were synthesized and characterized through the use of X-ray and neutron diffraction, and DC—magnetism measurements. All compositions of InGa1−xFexCuO4 are single phase and crystallize in the R  3¯m space group, but a transformation to the spinel InFeMgO4 structure was observed for the other series of Fe3+ and Mg2+—rich compounds. As a result of the similar ionic radii for Ga3+ and Fe3+, there was not an obvious change in the c/a ratio for InGa1−xFexCuO4. In the hexagonal domains, the c/a ratio of InFeCu1−xMgxO4 and InGa1−xFexCu1−xMgxO4 showed a linear trend that can be explained by the change in electronic configurations between Cu2+ and Mg2+. All hexagonal compositions display negative Weiss temperatures, and there is an increase in the magnetic transition temperature with the addition of Fe3+. Additional AC magnetic susceptibility measurements for the x=0.4 and 0.6 compositions within the InGa1−xFexCuO4 solid solution show that these transitions are consistent with spin glass behavior, not long range AFM ordering.

Solid solutions of InGa1−xFexCuO4, InFeCu1−xMgxO4 and InGa1−xFexCu1−xMgxO4 have been synthesized and analyzed with powder X-ray and neutron diffraction, and DC magnetism measurements. The influence of the trigonal bipyramidal site has been investigated through cation substitutions of ionic radii similarities and electronic configuration differences.Figure optionsDownload as PowerPoint slideHighlights
► Solid solutions of InM3+M2+O4 (M3+=Ga, Fe; M2+=Cu, Mg) have been synthesized.
► A complete solid solution was achieved for the hexagonal InGa1−xFexCuO4.
► Samples with high Fe/Mg content contained both the hexagonal and spinel phases.
► Spin glass magnetic interactions were observed in the hexagonal samples.