µSr study of organic systems: ferromagnetism, antiferromagnetism, the spin-crossover effect, and fluctuations in magnetic nanodiscs

Stephen J. Blundell (1) , Francis L. Pratt (2) , Tom Lancaster (1) , Ishbel M. Marshall (1) , Christopher A. Steer (1) , W. Hayes (1) , Tadashi Sugano (3) , Jean-François Létard (4) , Andrea Caneschi (5) , D. Gatteschi (5) , Sarah L. Heath (6)

1 Clarendon Laboratory
2 ISIS - ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​ISIS Neutron and Muon Source
3 Department of Chemistry [Yokohama]
4 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
5 LAMM - Dipartimento di Chimica & UdR INSTM
6 Department of Chemistry [York, UK]

We present the results of recent μSR experiments on a variety of novel organic and molecular magnetic systems. Muons are sensitive to local static fields and magnetic fluctuations, but can probe much more than just the onset of long-range magnetic order. We review our work on nitronyl nitroxide organic ferromagnets and antiferromagnets. We describe a muon study of the spin-crossover phenomenon which has been studied in Fe(PM-PEA)2(NCS)2, and which shows Gaussian and root-exponential muon relaxation in the high-spin and low-spin phases, respectively. Experiments on a disc-shaped molecular complex containing Fe19 (with spin Image) reveal the effects of quantum tunneling of magnetization and allow an estimate of the quantum tunneling rate.

Mots clés: Organic magnet; Nanodisc; Quantum tunneling; Molecular magnet

Domaines: Matériaux

Stephen J. Blundell, Francis L. Pratt, Tom Lancaster, Ishbel M. Marshall, Christopher A. Steer, et al.. µSr study of organic systems: ferromagnetism, antiferromagnetism, the spin-crossover effect, and fluctuations in magnetic nanodiscs. Physica B: Condensed Matter, 2003, 326 (1-4), pp.556-562. ⟨10.1016/S0921-4526(02)01688-5⟩. ⟨hal-00221379⟩