Fe-57 Mossbauer, infrared and X-ray studies of the system Zn1-xCuxCr0.8Fe1.2O4

Spectral studies of the cubic spinel ferrites Zn1-xCuxCr0.8Fe1.2O4, 0 less than or equal to x less than or equal to 1 are carried out at room temperat ure by X-ray, Mossbauer and IR spectra. The deduced X-ray parameters have b een studied as functions of x. The average and true lattice parameters ((a) over bar and a(0)), the theoretical and bulk densities (D-X and D), and th e porosity P were determined for all samples. The positional oxygen paramet er II, the tetrahedral and octahedral ionic radii (r(A) and r(B)), the tetr ahedral and octahedral bond lengths (d(AX) and d(BX)), the tetrahedral and shared and unshared octahedral edges (d(AE), d(BE) and d(BEU)), have been c alculated and deduced. It has been found that (a) over bar decreases and D- X increases with x less than or equal to 0.6 and the opposite behaviour tak es place with x > 0.6. Except x = 0, D decreases and P increases with x. Th e parameters a(0), u, r(A), d(AX), d(AE) and d(BEU) decrease with x while r (B), d(BX) and d(BE) increase. The room temperature Mossbauer spectra showe d that the samples with x less than or equal to 0.6 are paramagnetic while the samples with x > 0.6 are ferrimagnetic. The determined hyperfine intera ction parameters as functions of x have been studied and discussed. The car ion distributions have been determined. The infrared studies confirmed the presence of four peaks. These peaks were nu (1), nu (2), nu (3) and nu (4) and assigned to the tetrahedral A-site, octahedral B-sites, divalent ions a t B-sites and lattice vibrations, respectively.