Williamson-Hall strain analysis, cation distribution and magnetic interactions in Dy³⁺ substituted zinc-chromium ferrite

In the present work, a detailed investigation has been carried out on nanocrystalline particles of ZnCr0.5DyxFe1.5-xO4 with x = 0.0, 0.025, 0.05, 0.075 and 0.1 to estimate intrinsic strain through Williamson-Hall (W-H) analysis. The results were compared with those obtained from Scherrer equation and Rietveld refinement. Bertaut method was used to estimate the cation distribution of spinel ferrite. The structural, morphological and magnetic properties were studied by X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy and vibrating sample magnetometer. XRD analysis confirmed the cubic spinel structure of the prepared samples without the presence of any impurity and secondary phases. Selected area electron diffraction and IR measurements gives further confirmation to the XRD observation. Lattice constant increased from 8.398 to 8.409 Å and lattice strain increased from 2.96 × 10−4 to 5.88 × 10−4 with the increase in Dy substitution. Considering that strain mechanism and cation distribution play a major role for controlling the magnetic properties and therefore these properties were precisely evaluated through reliable methodology using XRD and magnetization data. Saturation magnetization of the system increased from 13.15 to 27.6 emu/g and coercivity increased from 42 to 672 Oe with the Dy substitution. The cation distribution determined by X-ray diffraction data are supported by the magnetization studies. The mechanisms involved are discussed in the manuscript