Abstract
Quantum tunneling of the magnetization in magnetic molecules (MM) with high spin value is a fascinating subject which contrasts clean and accurate experimental data with sophisticated theoretical models. At the heart of these models stands the Landau [1] and Zener [2] (LZ) derivation of quantum tunneling between levels, which at resonance have a tunnel splitting Δ, but are brought in to and out off resonance by a time-dependent field. This theory predicts transition probabilities, however, it has not been able to account for the size of the magnetization jumps in molecular magnets. In fact, the discrepancy between Δ deduced from LZ experiments [3] and the one calculated from spectroscopic data is more than three orders of magnitudes [4]. In these circumstances it might be essential to analyze experiments using a broader LZ theory which includes stochastic fluctuations produced by the environment. Such a theory was developed by Shimshoni and Stern (SS) [5]. The SS theory takes into account the dephasing effect due to stochastic field fluctuations. Combining this theory with measurements of dephasing times for MM could lead to a revision in tunnel splitting calculations. But, as far as we know, there are no estimates for dephasing time of MM. The purpose of the present work is to highlight the importance of dephasing in tunneling experiments and to measure the dephasing time.
Access provided by Autonomous University of Puebla. Download to read the full chapter text
Chapter PDF
Similar content being viewed by others
Keywords
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
References
L. D. Landau, Phys. Z. Sov. 2, 46 (1932).
C. Zener, Proc. Roy. Soc. (London) A 137, 696 (1932).
W. Wernsdorfer, R. Sessoli, A. Caneschi, and D. Gatteschi, A. Cornia, and D. Mailly, J. Appl. Phys. 87, 5481 (2000).
S. Carretta, E. Liviotti, N. Magnani, P. Santini, and G. Amoretti, Phys. Rev. Lett. 92, 207205 (2004).
E. Shimshoni and A. Stern, Phys. Rev. B 47, 9523 (1993).
K. Mullen, E. Ben-Jacon, Y. Gefen, and Z. Schuss, Phys. Rev. Lett. 62, 2543 (1989).
E. Shimshoni and Y. Gefen, Ann. of Phys. 210, 16 (1991).
Z. Salman, A. Keren, P. Mendels, V. Marvaud, A. Scuiller, and M. Verdaguer, Phys. Rev. B 65, 132403 (2002).
Z. Salman, A. Keren, P. Mendels, A. Scuiller and M. Verdaguer, Physica B 289–290, 106 (2000).
T. Mallah, C. Auberger, M. Verdaguer and P. Veillet, J. Chem. Soc., Chem. Commun., 61 (1995).
T. Mallah, S. Ferlay, A. Scuiller and M. Verdaguer, Molecular Magnetism: a Supramolecular Function, NATO ASI series, C474, Reidel, Dordrecht, 597 (1996).
A. Scuiller, T. Mallah, M. Verdaguer, A. Nivorozkhin, J. L. Tholence and P. Veillet, New J. Chem. 20, 1 (1996).
A. Barra and M. Verdaguer, Private communication.
Author information
Authors and Affiliations
Rights and permissions
Copyright information
© 2007 Springer-Verlag Italia
About this chapter
Cite this chapter
Keren, A. (2007). Stochastic Landau-Zener model, and experimental estimates of dephasing time in molecular magnets. In: NMR-MRI, μSR and Mössbauer Spectroscopies in Molecular Magnets. Springer, Milano. https://doi.org/10.1007/978-88-470-0532-7_8
Download citation
DOI: https://doi.org/10.1007/978-88-470-0532-7_8
Publisher Name: Springer, Milano
Print ISBN: 978-88-470-0531-0
Online ISBN: 978-88-470-0532-7
eBook Packages: Physics and AstronomyPhysics and Astronomy (R0)