Structural and magnetic properties of LaBa1-xSrxCuFeO5+δ and YbBa1-xSrxCuFeO5+δ (x = 0, 0.25 and 0.5) ceramic systems

We present a systematic study of structural and magnetic properties of LaBa1-xSrxCuFeO5+δ (La-x) and YbBa1-xSrxCuFeO5+δ (Yb-x) (x = 0.0, 0.25 and 0.5) ceramic compounds, synthesized with solid-state method. X-ray powder diffraction (XRD) technique indicates that La-x and Yb-x systems present single phases consistent with an orthorhombic symmetry (space group Immm (71)) and tetragonal symmetries (space group P4mm (99)), respectively, and a decreasing lattice parameter as the content of Sr increases. The results of infrared spectrums show the typical energy bands of a perovskite with a layered structure, and surface morphologic analysis evidenced the formation of polycrystalline material with diverse grain shape. The compositional characterization, obtained via the energy-dispersive X-ray spectroscopy technique, suggests that we achieve the desired material stoichiometry with the absence of impurities. Finally, vibrating sample magnetometry measurements evidenced an antiferromagnetic transition at a temperature around the 160 K only for x = 0, which is attributed to the dominant magnetic moments of rare earth ions.