Deterministic spontaneous avalanches in molecular magnetsA. Hernández-Mínguez1, F. Macià1, J. M. Hernandez1, J. Tejada1, L. H. He2 and F. F. Wang2
1 Departament de Física Fonamental, Facultat de Física, Universitat de Barcelona Avda. Diagonal 647, Planta 4, Edifici nou, 08028 Barcelona, Spain
2 State Key Laboratory for Magnetism, Institute of Physics and Centre of Condensed Matter Physics, Chinese Academy of Sciences P.O. Box 603, Beijing 100080, PRC
received 29 May 2006; accepted in final form 18 July 2006
published online 4 August 2006
In this paper we discuss experimental data for the magnetic avalanches associated to the spin quantum reversal in large single crystals of (Mn0.96Cr0.04)-acetate. We have studied the ignition of the magnetic avalanche by sweeping the applied magnetic field at different temperatures in the presence of a magnetic-field gradient along the c-axis (easy axis of magnetization) of the single crystal. Our results show both the determininistic nature of the occurrence of the avalanche at the resonant fields and the fact that the avalanche is always ignited at the extreme of the crystal where the magnetic field is larger. A theoretical model is discussed to explain the results.
75.50.Xx - Molecular magnets.
45.70.Ht - Avalanches.
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