Determination of Phase Composition of Cobalt Nanoparticles Using Co-59 Internal Field Nuclear Magnetic Resonance

Manjunatha, M and Reddy, G Srinivas and Mallikarjunaiah, K J and Damle, Ramakrishna and Ramesh, K P (2019) Determination of Phase Composition of Cobalt Nanoparticles Using Co-59 Internal Field Nuclear Magnetic Resonance. In: JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM, 32 (10, SI). pp. 3201-3209.

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Abstract

It is well known that cobalt exhibits polymorphism, i.e., the co-existence of both the hcp and fcc phases. In particular, the method of synthesis and other thermodynamic conditions is known to play a crucial role in determining the particular phase of cobalt. In this work, we have compared the phase composition of the cobalt nanoparticles synthesized using two different solvents (water) and ethanol (Co@C). XRD measurements confirm the existence of fcc phase in commercial cobalt nanoparticles (Co@A), co-existence of fcc and hcp phases in Co@B, while the existence of the hcp phase in Co@C. We have studied these cobalt nanoparticles using Co-59 internal field nuclear magnetic resonance (IFNMR) for verification of phase composition. Our studies reveal that the Co@A has fcc as a major phase with minor quantity hcp phase. Co@B exhibits approximately equal amount of fcc and hcp phase while Co@C exhibits hcp as a major phase with minor fcc phase. Our SEM micrograph studies confirm that the cobalt particles have spherical shape in the fcc phase. The cobalt particles exhibit both spherical and dendrite morphology confirming the co-existence of fcc and hcp phases, while the sample with pure hcp phase exhibits the dendrite morphology. Our studies also throw light on understanding the effect of solvent in the phase formation of the cobalt nanoparticles.

Item Type:	Journal Article
Publication:	JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM
Publisher:	SPRINGER
Additional Information:	Copyright of this article belongs to SPRINGER
Keywords:	Co-59 IFNMR; NMR line shape analysis; Cobalt nanoparticles; Solvent viscosity; Phase composition
Department/Centre:	UG Programme Division of Physical & Mathematical Sciences > Physics
Date Deposited:	16 Dec 2019 06:11
Last Modified:	16 Dec 2019 06:11
URI:	http://eprints.iisc.ac.in/id/eprint/64069

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