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Mardi 28 avril 2015-14:00

Molecular Spin Crossover Phenomenon at the nanoscale

Azzedine Bousseksou (Laboratoire de Chimie de Coordination, Toulouse)

par Gabriel LeMarié - 28 avril 2015

Word - 197 ko

The spin crossover phenomenon in inorganic materials is one of the most spectacular examples of molecular bistability, which means that these molecules may exist in two different electronic states within a certain range of external perturbations. Most notably, the existence of a thermal hysteresis in certain complexes (in the solid state) confers a memory effect on these systems [1-4]. In our group we are particularly interested in the synthetic elaboration of nanometric thin films [5] and nano-sized patterns [6] that we obtain by electron beam lithography and in the application of an external perturbation in the hysteresis loop of spin crossover materials leading to an irreversible switching of their physical properties [4]. Recent hot results concerning the spatio-temporal spin propagation and visualisation of nucleation and growth of spin domains in spin crossover single crystals will be presented.

Besides generating new fundamental knowledge on size-reduction effects and the dynamics of the spin crossover phenomenon, this research aims also at the development of practical applications such as sensor, display, information storage and nanophotonic devices [1-12].

In this talk, I will discuss recent work in the field of molecule-based spin crossover materials with a special focus on these emerging issues, including chemical synthesis, physical properties, practical applications and theoretical aspects as well.

[1]- A. Bousseksou, et al Chem. Soc. Rev. (2011) Critical Review
[2]- S. Bedoui et al, Phys. Rev. Lett. 109 (2012) 135702. (2012)
[4]- S. Bonhommeau et al, Angew. Chem. Int. Ed. 44 (2005) 4069-4073.
[5]- S. Cobo et al, Angew. Chem. Int. Ed. 45 (2006) 5786-5789.
[6]- G. Molnar et al, Adv. Mater. 19 (2007) 2163-2167.
[7]- S. Cobo, J. Am. Chem. Soc. 130 (2008) 9019-9024.
[8]- T. Mahfoud et al, J. Am. Chem. Soc. 131 (2009) 15049-15054.
[9]- S. Cobo et al, J. NanoSci. Nanotech.10 (2010) 5042-5050.
[10]- M. Lopes et al, Nanoscale 5 (2013) 7762-7767.
[11]- H. Tran, F. Terki et al, Angew. Chem. Int. Ed. 52 (2013) 1185-1188.
[12]- H.J. Shepherd et al, Nature Commun. 4 (2013) 2607.

Post-scriptum :

contact : G. Lemarié