Relaxation time enhancement of cobalt zinc nanoferrites via Cr3+ doping

Abstract

Cation distribution, structure analysis, elastic moduli, magnetic and dielectric features obtained by the citrate combustion technique of Co0.8Zn0.2CrxFe2-xO4 (x = 0, 0.02, 0.04, 0.06, 0.08 and 0.1) (CZC) nanoferrites were investigated. The most intense (311) peak is found to gradually shift towards higher diffraction angles, and so the lattice constant is found to decrease (from 8.3893 to 8.3698 Å, experimentally) and (from 8.3893 to 8.3853 Å, theoretically), as the Cr3+ content increase. The crystallite size of CZC nanoferrites initially increases from 38 to 42 nm for Cr3+content (x = 0.0 to x = 0.06), and then decrease from x = 0.08 onwards. Morphological contemplation (FE-SEM, HRTEM) manifests that the porosity diminishes significantly with increasing Cr3+ content meanwhile the particles have some agglomeration. The elastic moduli and Poisson's ratio of CZC ferrite samples were determined, theoretically and experimentally, and then corrected to zero porosity using Hosselman and Fulrath's model. An analogous behavior for experimental and theoretical magnetic moment is obtained, attached with an increment attitude of Yafet–Kittel angle on the B-sublattice, which increase (from 39° 42′ to 41° 51′) as the Cr3+ content increase. The value of impedance is increased (from 44 k Ω to 203 k Ω) with increasing Cr3+ content. Nyquist plot shows a single semicircle declaring that the predominant conduction is through the grain boundary volume. These results behold that substitution with Cr ions and porosity has prominent impacts on the various properties of Co-Zn nanoferrites, making it nominee for multilateral applications. The loss of Co0.8Zn0.2Cr0.1Fe1.9O4 nanoferrite (x = 0.1) is decreased ∼ 4 times with increasing relaxation time from 0.53 to 15.9 μs, which has good predictions for next generation cores of RF transformers.