Effect of the magnetic field on the dynamics of the cooperative photoinduced spin-state transition and relaxation

This is a report on the magnetic field effect on the cooperative photoinduced spin-state transition process between low-spin (LS) and high-spin (HS) states in a spin-crossover complex. When the magnetic field is enhanced from 0.5 to 7 T, the transition temperature scarcely decreases only by about 0.2 K. In contrast photoconversion efficiency from LS to HS state and the relaxation time of photoconverted HS state to thermally stable LS increased by 7.1 and 1.5 times, respectively. An analytical approach of the relaxation in a tunneling regime is presented, including the effect of correlations and the magnetic field. This theoretical model explains well the experimental results.