Solvent dependent morphology and Co-59 internal field NMR study of Co-aggregates synthesized by a wet chemical method

Choudhary, Harish Kumar and Manjunatha, M and Damle, R and Ramesh, KP and Sahoo, B (2018) Solvent dependent morphology and Co-59 internal field NMR study of Co-aggregates synthesized by a wet chemical method. In: PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 20 (26). pp. 17739-17750.

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Abstract

Different shapes of Co-aggregates were synthesized via reduction of a Co salt (CoCl2<bold></bold>6H(2)O) by chemical precipitation using glycerol, ethylene glycol and ethanol as solvents. The effect of solvent on the morphology, fcc or hcp phase-content and the magnetic properties of the synthesized samples were investigated. The Co-aggregates synthesized using glycerol have a dense spherical shape and high saturation magnetization (M-S), whereas ethylene glycol leads to formation of flower-shaped spherical aggregates through loose packing of smaller plate-like particles which have a moderate M-S value. When ethanol was used as a solvent, a dendritic (leaf like)-shape of the aggregates with the lowest M-S value was obtained. The formation of the obtained morphology of the aggregates was explained based on the size of the solvent molecule, the viscosity of the solvent and the number of polar groups (-OH) present in the solvent molecules. The magnetic domain state and domain wall dynamics of all the Co-samples were investigated using Co-59 Internal Field Nuclear Magnetic Resonance (IFNMR) spectroscopy at RT and at 77 K. Through the IFNMR spectroscopy, the presence of gain boundaries, single domain particles and multi-domain particles/aggregates with domain walls associated with fcc and hcp phases were identified and quantified. We observed that the use of ethanol facilitates formation of a higher amount of hcp phase in the sample than the use of glycerol or ethylene glycol.

Item Type:	Journal Article
Publication:	PHYSICAL CHEMISTRY CHEMICAL PHYSICS
Publisher:	ROYAL SOC CHEMISTRY, THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND
Additional Information:	Copyright of this article belong to ROYAL SOC CHEMISTRY, THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND
Department/Centre:	Division of Chemical Sciences > Materials Research Centre Division of Physical & Mathematical Sciences > Physics
Date Deposited:	31 Jul 2018 15:28
Last Modified:	05 Mar 2019 04:58
URI:	http://eprints.iisc.ac.in/id/eprint/60324

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