Finite Size Effects on the Switching Dynamics of Spin-Crossover Thin Films Photoexcited by a Femtosecond Laser Pulse - Université de Rennes Accéder directement au contenu
Article Dans Une Revue Advanced Materials Année : 2019

Finite Size Effects on the Switching Dynamics of Spin-Crossover Thin Films Photoexcited by a Femtosecond Laser Pulse

Karl Ridier
William Nicolazzi
L. Salmon
Roman Bertoni
E. Collet
H. Cailleau

Résumé

Using ultrafast optical absorption spectroscopy, the room-temperature spin-state switching dynamics induced by a femtosecond laser pulse in high-quality thin films of the molecular spin-crossover (SCO) complex [Fe(HB(tz) ) ] (tz = 1,2,4-triazol-1-yl) are studied. These measurements reveal that the early, sub-picosecond, low-spin to high-spin photoswitching event, with linear response to the laser pulse energy, can be followed under certain conditions by a second switching process occurring on a timescale of tens of nanoseconds, enabling nonlinear amplification. This out-of-equilibrium dynamics is discussed in light of the characteristic timescales associated with the different switching mechanisms, i.e., the electronic and structural rearrangements of photoexcited molecules, the propagation of strain waves at the material scale, and the thermal activation above the molecular energy barrier. Importantly, the additional, nonlinear switching step appears to be completely suppressed in the thinnest (50 nm) film due to the efficient heat transfer to the substrate, allowing the system to retrieve the thermal equilibrium state on the 100 ns timescale. These results provide a first milestone toward the assessment of the physical parameters that drive the photoresponse of SCO thin films, opening up appealing perspectives for their use as high-frequency all-optical switches working at room temperature.
Fichier principal
Vignette du fichier
Ridier-2019-Finite Size Effects on the Switching Dynamics.pdf (1.3 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)
Loading...

Dates et versions

hal-02161140 , version 1 (01-07-2019)

Identifiants

Citer

Karl Ridier, Alin-Ciprian Bas, Victoria Shalabaeva, William Nicolazzi, L. Salmon, et al.. Finite Size Effects on the Switching Dynamics of Spin-Crossover Thin Films Photoexcited by a Femtosecond Laser Pulse. Advanced Materials, 2019, 31 (25), pp.1901361. ⟨10.1002/adma.201901361⟩. ⟨hal-02161140⟩
119 Consultations
253 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More