Influence of Zn concentration on the structural and magnetic properties of nanocrystalline Cu1−xZnxFe2O4 mixed ferrites synthesized using novel combustion method

Abstract

In this work, we report the structural and magnetic properties of nanocrystalline Cu1−xZnxFe2O4 mixed ferrites synthesized using novel combustion method. The prepared samples are spinel structured and the secondary phase α-Fe2O3 is also present in CuFe2O4. The size of the crystallites ranges between 9.6nm and 31nm and the lattice constant increases from 8.342Å to 8.435Å. The FTIR absorption bands of CuFe2O4 are observed at 571cm−1 and 409cm−1 for tetrahedral and octahedral sites, respectively. These bands are shifting to 547cm−1 and 397cm−1 for Zn substitution. Raman spectra show the change in local environment of tetrahedral and octahedral interstitial sites with Zn. The FE-SEM images show that the prepared samples are nano sized and the substitution of Zn decreases the agglomeration. The magnetic study reveals that the saturation magnetizations initially increases from 21.45emu/g (x=0) to 44.16emu/g (x=0.2) and then decreases at 300K. The superparamagnetic behavior is observed for samples of x≥0.4 concentration. The temperature dependent zero field cooled and field cooled magnetic measurements confirm the superparamagnetic nature and the observed blocking temperature decreases from 120.4K to 32.3K. The hysteresis curves measured at 20K show the coercivity and it varies from 663Oe to 70Oe for increasing Zn content.