Correlation between the magnetic-microstructure and microwave mitigation ability of MCoFeO based ferrite-carbon black/PVA composites.

Author(s) Datt, G.; Kotabage, C.; Datar, S.; Abhyankar, A.C.
Journal Phys Chem Chem Phys
Date Published 2018 Nov 07
Abstract

A study of controlling the microwave mitigation properties of ferrite-carbon black/PVA composites by tuning the magnetic microstructure and spin arrangement of the ferrite particles is presented. MCoFeO (M: Ni, Mn & Zn) nano-ferrites (NFs) were synthesized by a solvothermal method and these NFs were used to fabricate NF-CB hybrids and flexible NF-CB/PVA composite films. The magnetic force microscopy studies of the NFs reveal a unique single axis oriented domain structure for Zn-NFs and multi-domain magnetic microstructures for Mn-NFs and Ni-NFs. Mössbauer analysis of the NFs reveals highly distorted co-ordination of Fe cations in Zn-NFs, whereas sub-lattice spins are canted in Mn-NFs and Ni-NFs. Despite the distorted magnetic lattice and broken coordination, the largest microwave shielding effectiveness (SE) of 32 dB is observed, over a bandwidth of 8 to 18 GHz, for Zn-NF-CB/PVA with a major contribution from absorption (SE∼ 25 dB). The dielectric properties and Cole-Cole plots indicate enhanced interfacial polarization in Zn-NF-CB/PVA, which is attributed to the motion of polarons across multiple heterogeneous interfaces. These polarons are thought to be generated by distorted co-ordination of Fe, and d-d electron transition between Co⇋ Fe cations at the B-site of Zn-NF. Distorted co-ordination of Fe in Zn-NF along with unique single axis oriented magnetic domains play a crucial role in magnetic losses, as μ'' is almost double in Zn-NF based composites as compared to other composites. Due to their excellent and tunable microwave absorption properties, NF-CB/PVA composites could be employed for next generation stealth applications.

DOI 10.1039/c8cp05235b
ISSN 1463-9084
Citation Datt G, Kotabage C, Datar S, Abhyankar AC. Correlation between the magnetic-microstructure and microwave mitigation ability of MCoFeO based ferrite-carbon black/PVA composites. Phys Chem Chem Phys. 2018;20(41):26431-26442.

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