Scan-rate and vacuum pressure dependence of the nucleation and growth dynamics in a spin-crossover single crystal: The role of latent heat

Karl Ridier (1, 2) , Sylvain Rat (1, 2) , L. Salmon (1) , William Nicolazzi (1, 2) , Gábor Molnár (1) , Azzedine Bousseksou (1)

1 LCC - Laboratoire de chimie de coordination
2 UT3 - Université Toulouse III - Paul Sabatier

Using optical microscopy we studied the vacuum pressure dependence (0.1-1000 mbar) of the nucleation and growth dynamics of the thermally induced first-order spin transition in a single crystal of the spin-crossover compd. [Fe(HB(tz)3)2] (tz = 1,2,4-triazol-1-yl). A crossover between a quasi-static hysteresis regime and a temp.-scan-rate-dependent kinetic regime is evidenced around 5 mbar due to the change of the heat exchange coupling between the crystal and its external environment. Remarkably, the absorption/dissipation rate of latent heat was identified as the key factor limiting the switching speed of the crystal.

Domaines: Chimie de coordination

Karl Ridier, Sylvain Rat, L. Salmon, William Nicolazzi, Gábor Molnár, et al.. Scan-rate and vacuum pressure dependence of the nucleation and growth dynamics in a spin-crossover single crystal: The role of latent heat. Physical Chemistry Chemical Physics, 2018, 20 (14), pp.9139-9145. ⟨10.1039/C7CP08522B⟩. ⟨hal-01961777⟩