Heat Capacity and Thermal Damping Properties of Spin‐Crossover Molecules: A New Look at an Old Topic

Karl Ridier (1) , Yuteng Zhang (1) , Mario Piedrahita-Bello (1) , Carlos M. Quintero (1, 2) , Lionel Salmon (1) , Gábor Molnár (1) , Christian Bergaud (2) , Azzedine Bousseksou (1)

1 LCC - Laboratoire de chimie de coordination
2 LAAS-MEMS - Équipe Microsystèmes électromécaniques

The thermally induced spin-crossover (SCO) phenomenon in transition metal complexes is an entropy-driven process, which has been extensively studied through calorimetric methods. Yet, the excess heat capacity associated with the molecular spin-state switching has never been explored for practical applications. Herein, the thermal damping effect of an SCO film is experimentally assessed by monitoring the transient heating response of SCO-coated metallic microwires, Joule-heated by current pulses. A damping of the wire temperature, up to 10%, is evidenced on a time scale of tens of microseconds due to the spin-state switching of the molecular film. Fast heat-charging dynamics and negligible fatigability are demonstrated, which, together with the solid-solid nature of the spin transition, appear as promising features for achieving thermal energy management applications in functional devices.

Mots clés: Excess heat capacity; Molecular thin films; Spin-crossover; Thermal energy storage; Thermal management

Domaines: Chimie de coordination

Karl Ridier, Yuteng Zhang, Mario Piedrahita-Bello, Carlos M. Quintero, Lionel Salmon, et al.. Heat Capacity and Thermal Damping Properties of Spin‐Crossover Molecules: A New Look at an Old Topic. Advanced Materials, 2020, 32 (21), pp.2000987. ⟨10.1002/adma.202000987⟩. ⟨hal-02570846⟩