Synthesis of CuFe2O4 and Ni1 xZnxFe2O4 nanoparticles and study the effect of annealing temperature on their structure morphological magnetic and optical properties

Abstract

The analysis of structural characteristics of the ASP and annealed CuFe2O4 nanoparticles the corresponding is shown in Figure 4.1 which were observed by XRD patterns. As the XRD patterns suggest that for ASP and 200 °C samples the cubic spinel phase is confirmed and the characteristics peaks of these samples have been indexed as (220), (311), (422), (511) and (440) in agreement with JCPDS File Card No. 77 0010. As the temperature of annealing is increased to 400 °C and 600 °C peaks corresponding to tetragonal phase can be witnessed in XRD pattern with trace amount of cubic phase of figure 4.1. Along with the characteristic peaks for ASP and annealed samples up to 600 °C, certain additional peaks also have been marked and they confirmed the presence of small CuO and Fe2O3 phases. At 800 and 1000 °C, the cubic phase vanished and tetragonal phase of CuFe2O4 ferrite was detected as compared to JCPDS data (Card No. 34-0425). The variation from cubic to tetragonal could be assigned to the tetragonal disruption as said by Jahn-Teller effect (JTE) [Cnoradie, J. et al (2019); Qi, J. Q. et al (2005); Nowicki, W. et al (2011); Tailhades, P. et al (1998)]. The crystallite size of copper nano ferrite samples was computed by Debye Scherrer formula see equation (3.2) [Kanagaraj, M. et al (2014)]. The values of crystallite size, once compared from Figure 4.2, for all the annealed samples shows that as the annealing temperature increases there is a gradual increment in the crystallite size value. For ASP copper ferrite sample the crystalline size value is 10.9 nm and it attains the value of 34.8 nm for the annealing temperature 1000 °C. In addition, the sample heated at 400 °C there is a fall in the size of the crystallite size value appeared which may be due to change in copper ferrite phase from cubic to tetragonal. [Yadav, R.S. et al (2016)] observed, CuFe2O4 NPs size was decreased via 10.9 nm (200 °C) to 10.8 nm - 10.5 nm (500 °C) in cubic and tetragonal phase respectively and thereafter, an increased