Figure 1

Typical switching experiments at low temperature for spin transition compounds (a) Sigmoidal relaxation of $\left[{\mathrm{Fe}}_{0.3}{\mathrm{Zn}}_{0.7}{\left(\mathrm{btr}\right)}_2{\left(\mathrm{N}\mathrm{C}\mathrm{S}\right)}_2\right]\bullet {\mathrm{H}}_2\mathrm{O}$ in the dark. The relaxation rate is an increasing function of temperature. (b) Photoconversion of $\left[{\mathrm{Fe}}_{0.3}{\mathrm{Zn}}_{0.7}{\left(\mathrm{btr}\right)}_2{\left(\mathrm{N}\mathrm{C}\mathrm{S}\right)}_2\right]\bullet {\mathrm{H}}_2\mathrm{O}$ at $10\mathrm{K}$, $550\mathrm{nm}$, from LS ground state to metastable HS state for intensity values 4, 6, and $12\mathrm{mW}∕{\mathrm{cm}}^2$. Note that the photoexcitation rate is an increasing function of intensity of light. (c) Competition between photoexcitation and relaxation of $\left[{\mathrm{Fe}}_{0.52}{\mathrm{Ni}}_{0.48}{\left(\mathrm{btr}\right)}_2{\left(\mathrm{N}\mathrm{C}\mathrm{S}\right)}_2\right]\bullet {\mathrm{H}}_2\mathrm{O}$ at under permanent irradiation with a $550\mathrm{nm}$ wavelength, at $41\mathrm{K}$, evidencing the light-induced bistability of the system; inset is the LITH loop. Intensity: $6\mathrm{mW}∕{\mathrm{cm}}^2$, temperature scanning rate: $0.03\mathrm{K}∕\min$.Reuse & Permissions

Figure 2

Experimental FORCs at the thermal transition of $\left[{\mathrm{Fe}}_{0.6}{\mathrm{Zn}}_{0.4}{\left(\mathrm{btr}\right)}_2{\left(\mathrm{N}\mathrm{C}\mathrm{S}\right)}_2\right]\bullet {\mathrm{H}}_2\mathrm{O}$ and corresponding FORC diagrams, from reflectivity data.Reuse & Permissions

Figure 3

Light-induced thermal hysteresis: Typical FORCs in the cooling (top) and warming (bottom) modes, with the corresponding distributions reported in the two halves of the same Preisach plane.Reuse & Permissions

Figure 4

(Color online) $\left[{\mathrm{Fe}}_{0.6}{\mathrm{Zn}}_{0.4}{\left(\mathrm{btr}\right)}_2{\left(\mathrm{N}\mathrm{C}\mathrm{S}\right)}_2\right]\bullet {\mathrm{H}}_2\mathrm{O}$. Experimental LITH/FORCs, for different temperature sweep rates and light intensities, from reflectivity data.Reuse & Permissions

Figure 5

Derived LITH/FORC distribution of the switching temperatures: from top to bottom. $0.42\mathrm{K}∕\min$, $I_1$; $0.42\mathrm{K}∕\min$, $I_2>I_1$; $0.3\mathrm{K}∕\min$, $I_2$. The main distribution peak becomes steeper for lower sweeping rate or larger light intensity.Reuse & Permissions

Figure 6

$\left[{\mathrm{Fe}}_{0.6}{\mathrm{Zn}}_{0.4}{\left(\mathrm{btr}\right)}_2{\left(\mathrm{N}\mathrm{C}\mathrm{S}\right)}_2\right]\bullet {\mathrm{H}}_2\mathrm{O}$ (a) LITH/FORCs simulated in the warming mode at the experimental temperature scan and for comparison the experimental major loop and two reversal curves of Fig. 4. (b) Similar simulations at various scan rates.Reuse & Permissions

Figure 7

LITH/FORC distribution for the warming mode, at different scan rates. The hatched areas indicate negative FORC distributions.Reuse & Permissions

Figure 8

The FORC diagrams for the two branches are perfectly mirroring if the temperature scanning rate is slow enough (simulations ${10}^{-5}\mathrm{K}∕\mathrm{s}$) (a) but are very different for high scanning rates (simulations ${10}^{-2}\mathrm{K}∕\mathrm{s}$) (b).Reuse & Permissions

Figure 9

Influence of the intensity on the light-induced thermal hysteresis with FORC curves and diagrams. From left to right, simulations obtained for increasing values: $I_1=0.000047{\mathrm{s}}^{-1}$, $I_2=10I_1$, $I_3=100I_1$, $I_4=500I_1$.Reuse & Permissions