Physical Review B (Condensed Matter and Materials Physics) -- May 1, 2000 -- Volume 61, Issue 18, pp. 12241-12248

Spin fluctuations in the spin-Peierls compound MEM(TCNQ)₂ studied using muon spin relaxation

B. W. Lovett, S. J. Blundell, F. L. Pratt, Th. Jestädt, and W. Hayes

Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom

S. Tagaki

Department of Physics, Kyushu Institute of Technology, Tobata, Kitakyushu 804, Japan

M. Kurmoo

IPCMS, 23 rue du Loess, BP 20/CR, 67037 Strasbourg Cedex, France

(Received 22 March 1999; revised 3 November 1999)

We report a muon spin relaxation (µSR) investigation of the organic spin-Peierls compound MEM(TCNQ)₂ at temperatures down to 39 mK. We have observed a slowing down of the electronic spins as the spin-Peierls gap widens at temperatures below the spin-Peierls transition and use this behavior to estimate the size of the gap. At the very lowest temperatures the electronic spin fluctuations freeze out and the muon spin depolarization is dominated by a persistent static mechanism which we ascribe to a defect-spin system. We relate the low-temperature depolarization rate to the concentration of these defects, and we propose a model for the creation of spin defects by the muon itself. ©2000 The American Physical Society

URL: http://publish.aps.org/abstract/PRB/v61/p12241
PACS: 76.75.+i, 75.25.+z, 75.40.Gb      Additional Information

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