Light-perturbed hysteresis in an iron(II) spin-crossover compound observed by the Mossbauer effect

The compound [Fe(phy)(2)](BF4)(2) (phy=1,10-phenanthroline-2-carbaldehyde phenylhydrazone) shows spin-transition with a hysteresis of 10 K width around room temperature. Continuous irradiation of the compound during heating and cooling with green light (514 nm) shifts the hysteresis in temperature.