Relaxation oscillations during the laser-induced spin state transition of a [Fe(PM-BiA)_{2}(NCS)_{2}] complex

Benjamin Viquerat (1) , Jérôme Degert (1) , Jean-François Létard (2) , Eric Freysz (1)

1 LOMA - Laboratoire Ondes et Matière d'Aquitaine
2 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux

We performed an optical pump-probe experiment to monitor the laser-induced spin state transition of [Fe(PM-BiA)2(NCS)2] spin crossover microcrystallites. The sample is illuminated by a continuous-wave pump laser centered at λ = 976 nm that switches the compound from the low-spin to the high-spin state. When the pump laser is switched on or off, and above a given power threshold, the diffuse reflectivity of the sample increases or decreases, respectively, and presents characteristic damped oscillations that are not due to laser-induced excited spin state trapping. We propose a shell-core model that, due to the laser-induced heating and spin state transition of the microcrystallites, accounts very well for the reported observations.

Mots clés: Nonequilibrium and irreversible thermodynamics; Heat conduction; Optical properties of bulk materials and thin films

Domaines: Optique [physics.optics]

Benjamin Viquerat, Jérôme Degert, Jean-François Létard, Eric Freysz. Relaxation oscillations during the laser-induced spin state transition of a [Fe(PM-BiA)_{2}(NCS)_{2}] complex. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2013, 87 (2), pp.024303 (1-6). ⟨10.1103/PhysRevB.87.024303⟩. ⟨hal-00790590⟩