Triggering the spin-crossover of Fe(phen)2(NCS)2 by a pressure pulse.: Pressure and magnetic field induce 'mirror effects'

We have studied the static and dynamic effects of pressure on the spin-transition in the temperature range of the thermal hysteresis loop for the compound Fe(phen)(2)(NCS)(2). The high-spin fraction (n(HS)) as a function of pressure and temperature has been determined by optical reflectivity. In this compound, the pressure was found to upward shift the spin-transition temperature by 23 K per kbar. During the dynamic pressure pulse, a decrease in n(HS) is observed, with an irreversible (reversible) character in the descending (ascending) branch of the hysteresis loop. In this respect, pressure has a 'mirror effect' compared to the application of an intense and pulsed magnetic field, for which - as reported previously - an increase in n(HS) is observed, with an irreversible (reversible) character in the ascending (descending) branch of the hysteresis loop.