Sol-Gel Synthesis and Structure-Property Relations in Zn_xCu_1-xBi₂O₄ (0≤ x ≤0.6) Spinels

Studies on ZnxCu1-xBi2O4(0≤ x ≤0.6) spinels (S1-S5: x = 0.0, 0.15, 0.3, 0.45, 0.6) were done using varieties of structure sensitive techniques. The powder X-ray diffraction (XRD) studies shows formation of cubic phase, a=10.6023 Ǻ, space group, Ia3, Z=3 in all the samples. The IR spectral results show the presence of octahedral[CuO6/2] or [BiO6/2] units and Bi-O, Cu-O, and Zn-O bonds in the samples. From the trend g║>g┴>ge(ge=2.0023) obtained from electron paramagnetic resonance(EPR) lineshapes simulation we conclude that the paramagnetic site in these glasses is Cu2+(3d9) which is in a tetragonally elongated octahedron [O1/2-CuO4/2-O1/2] exhibiting Jahn-Teller distortion having D4h symmetry with orbital singlet 3dx 2-y 2(2B1g) as the ground state.