Dynamic triggering of a spin-transition by a pulsed magnetic field

We report the first study of the effect of a high pulsed magnetic field on a spin transition complex in the solid state. The high spin fraction was de termined by optical reflectivity. Sizeable effects are observed for the wel l-known spin transition solid Fe(Phen)(2)(NCS)(2). In the hysteresis loop t emperature range, an increase in the BS fraction is obtained, with an irrev ersible (reversible) character in the ascending (descending) branch of the loop. The time dependence of the HS fraction provides information on the ki netics of the spin-crossover process at the spin transition.