Unified dynamical description of pulsed magnetic field and pressure effects on the spin crossover phenomenon

Sébastien Bonhommeau (1, 2) , Gábor Molnár (1) , Michel Goiran (3) , Kamel Boukheddaden (4) , Azzedine Bousseksou (1)

1 LCC - Laboratoire de chimie de coordination
2 Laboratoire Physique des Solides de Toulouse
3 LNCMP - Laboratoire National des Champs Magnétiques Pulsés
4 LMOV - Laboratoire de magnétisme et d'optique de Versailles

The effects of pulsed magnetic fields and pressure on the spin crossover phenomenon between high-spin and low-spin electronic states in ferrous compounds are investigated by introducing a model based on a macroscopic master equation written in the mean-field approximation. A bidirectional transition is predicted on the spontaneous thermal hysteresis and the light-induced thermal hysteresis (LITH) loops. The model also witnesses that a pressure pulse displays a mirror effect compared to a pulse of magnetic field and that different behaviors can be obtained depending on the intensity and shape of these pulses. In particular, we found that a rather long (∼1s) external perturbation must be used to reach a maximal spin conversion. In addition, the pulse intensity necessary to trigger a transition on the LITH loop is at least 30 times higher than for a spontaneous thermal hysteresis loop. As a final theoretical point, the correlation between the cooperativity and the response to a pulsed excitation is presented.

Domaines: Supraconductivité [cond-mat.supr-con]

Sébastien Bonhommeau, Gábor Molnár, Michel Goiran, Kamel Boukheddaden, Azzedine Bousseksou. Unified dynamical description of pulsed magnetic field and pressure effects on the spin crossover phenomenon. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2006, 74 (6), pp.064424-1-8. ⟨10.1103/PhysRevB.74.064424⟩. ⟨hal-00120785⟩