The interplay between the spin transition and the crystallographic phase transition in the fe(II) spin-crossover system [Zn1−xFex(ptz)6](BF4)2 (x = 0.1, 1;ptz= 1-propyltetrazole)

Temperature and pressure effects on the spin state of ferric ions in the [Fe(sal2-trien)][Ni(dmit)2] spin crossover complex

“…The most obvious explanation of this phenomenon can be a pressure induced additional structural change, since the sharp discontinuity in the phase diagram below 0.5 kbar, followed by a "regular" ClausiusClapeyron behaviour above 0.5 kbar is very difficult to explain in any other ways. However, a few different explanations for this unusual phenomenon can also be mentioned, such as cracks of particles which is not expected in our case where the hydrostatic conditions were maintained during the experiments and which should result, in any case, in a more gradual transition and narrowing of the hysteresis [43]. The variation of thermodynamic parameters could also affect the hysteresis width.…”

Quasi-static nature of the light induced thermal hysteresis in [Fe(ptz)6](BF4)2 spin-transition solid

“…We conclude that the quasi-statistic LITH is closely related to relatively high cooperativity of the title compound in the R3i crystallographic phase (a= 5,14). For the other crystallographic phase, P1i, the LITH loop is not observed.…”

“…Upon slow cooling, the crystal undergoes a crystallographic phase transition from the rhombohedric to the triclinic phase at T c ¡ =128 K and T c =135 K [5,6,10]. To study the behavior in the rhombohedric phase, we quenched it by rapid cooling (from 200 to 50 K in less than 3 min).…”

“…It was cooled down rapidly, from 200 to 50 K in less than 3 min, in order to quench the rhombohedric (high-temperature) crystallographic phase [2,5]. The magnetic signal was optimized at 10 K. Temperature dependent scanning measurements were performed.…”

“…Elastic interactions are related to the important difference in volume between the two spin states (DV HL :5%) [5]. The hysteresis itself originates from a coupling between the spin transition and a crystallographic phase transition [5,6].…”