The effect of zinc substitution and heat treatment on microstructural and magnetic properties of Li ferrite nanoparticles

Lithium-based ferrites are promising attractive and potential magnetic materials for many applications in technology. The influence of zinc substitution as well as the annealing temperature on phase formation, microstructure and magnetic characterizations of Li-ferrite were explored. The compositions were synthesized using the citrate method. The achieved ashes were annealed at three various temperatures 600, 800 and 1000 degrees C. The XRD analysis designated that the structure of as-prepared nanoparticles was promoted with the annealing. The surface examination of the as-prepared ashes showed that most of the particles are spherical in shape besides some agglomerated particles. The evaluated crystallite size ranged from 16 to 51 nm, indicating the fabrication of nano-crystalline particles. Magnetic characterizations displayed that M-s increased with the inclusion of Zn ions up to x = 0.2 and then slowly decreased for x > 0.2. The variation in both experimental and theoretical magnetic moments with Zn content was discussed for the compositions annealed at 1000 degrees C. The increment in M-s with zinc substitution was discussed using Neel's theory. Meanwhile, the decrement in M-s for x> 0.2 follows the Yafet-Kittel (Y-K) model. The rise in Y-K angles for x > 0.2 designated the better favor for triangle spin arrangements on B-sites. Moreover, M-s displayed an increasing behavior with elevating the annealing temperature to 1000 degrees C. Both coercivity (H-C) and remanence magnetization (M-r) decreased significantly with zinc content. (C) 2020 Elsevier B.V. All rights reserved.