On-off optical switching of the magnetic and structural properties in a spin-crossover complex

A photoexcitation is one of the promising external fields to control the material phases. Here, the authors have demonstrated that the magnetic and structural properties of a spin-crossover complex, Fe(phen)2(NCS)2 (phen=1,10-phenanthroline), can be reversibly switched by the on-off action of the continuous photoexcitation at the same temperature. The structural data suggest that the density of the high-spin Fe2+ in the photoinduced phase is about 0.88. Suppressed atomic vibrations of the photoinduced phase exclude the conventional heating effect as the origin for the observed optical switching.