Order-disorder phase transition and multiferroic behaviour in a metal organic framework compound (CH3)(2)NH2Co(HCOO)(3)

Yadav, Ruchika and Swain, Diptikanta and Bhat, HL and Elizabeth, Suja (2016) Order-disorder phase transition and multiferroic behaviour in a metal organic framework compound (CH3)(2)NH2Co(HCOO)(3). In: JOURNAL OF APPLIED PHYSICS, 119 (6).

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Abstract

We have investigated the multiferroic and glassy behaviour of metal-organic framework (MOF) material (CH3)(2)NH2Co(CHOO)(3). The compound has perovskite-like architecture in which the metal-formate forms a framework. The organic cation (CH3)(2)NH2+ occupies the cavities in the formate framework in the framework via N-H center dot center dot center dot O hydrogen bonds. At room temperature, the organic cation is disordered and occupies three crystallographically equivalent positions. Upon cooling, the organic cation is ordered which leads to a structural phase transition at 155 K. The structural phase transition is associated with a para-ferroelectric phase transition and is revealed by dielectric and pyroelectric measurements. Further, a PE hysteresis loop below 155 K confirms the ferroelectric behaviour of the material. Analysis of dielectric data reveal large frequency dispersion in the values of dielectric constant and tan delta which signifies the presence of glassy dielectric behaviour. The material displays a antiferromagnetic ordering below 15 K which is attributed to the super-exchange interaction between Co2+ ions mediated via formate linkers. Interestingly, another magnetic transition is also found around 11 K. The peak of the transition shifts to lower temperature with increasing frequency, suggesting glassy magnetism in the sample. (C) 2016 AIP Publishing LLC.

Item Type:	Journal Article
Publication:	JOURNAL OF APPLIED PHYSICS
Publisher:	AMER INST PHYSICS
Additional Information:	Copy right for this article belongs to the AMER INST PHYSICS, 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit Division of Physical & Mathematical Sciences > Physics
Date Deposited:	02 Apr 2016 07:09
Last Modified:	02 Apr 2016 07:09
URI:	http://eprints.iisc.ac.in/id/eprint/53553

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