Topological ferrimagnetism and superparamagnetic-like behaviour in a disordered homometallic coordination network

Patel, R., Weller, M.T. and Price, D.J. (2007) Topological ferrimagnetism and superparamagnetic-like behaviour in a disordered homometallic coordination network. Dalton Transactions, 2007(36), pp. 4034-4039. (doi: 10.1039/b706829h)




Crystals of a cobalt(II) 3-amino-1,2,4-triazolate; Co2Cl(C2N4H3)3, 1 can be formed from a hydrothermal synthesis. X-Ray crystallography shows an extended 3-dimensional network structure within a hexagonal space group with a = 9.9655(7) and c = 7.7523(7) Å. The data reveal an orientational disorder to the ligand. Structural considerations suggest that the ligand orientation is strongly correlated in 1-dimension, but the nature and length scale of the 2-dimensional order is not obvious. The structure is discussed in terms of three key structural models, two of which are crystallographically ordered, while the third is disordered in 2-dimensions. The effect of ligand orientation on the network topology has profound effects on the expected magnetic behaviour, with the two fully ordered models having either antiferromagnetic or ferrimagnetically ordered ground states. The magnetism of 1 is complex. It shows an antiferromagnetically coupled paramagnetic phase above 5.3 K. Below 4.5 K we see a ferrimagnetically ordered state (Hcoer = 50 Oe, Mrem = 1830 Oe cm3 mol−1, Msat = 3450 Oe cm3 mol−1 at 2 K). In the intermediate temperature range 4.5 to 5.3 K we see unusual behaviour with evidence of rapid, low-energy relaxation of the magnetisation. The unusual relationship between the structure and the magnetism of 1 is discussed in detail.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Price, Dr Daniel
Authors: Patel, R., Weller, M.T., and Price, D.J.
College/School:College of Science and Engineering > School of Chemistry
Journal Name:Dalton Transactions
Publisher:Royal Society of Chemistry
Published Online:21 August 2007
Copyright Holders:Copyright © 2007 Royal Society of Chemistry
First Published:First published in Dalton Transactions 2007(36):4034-4039
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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