Hard-X-ray-induced thermal hysteresis (HAXITH) in a molecular switchable solid

In this contribution, we report the first hard-X-ray-induced thermal hysteresis (HAXITH). The bistability in [Fe(phen)2(SCN)2] (phen = 1,10-phenanthroline) is proven by alternately heating and cooling the sample under permanent irradiation with hard X-rays. Within the hysteresis a serpentine-like switching effect is observed. HAXITH is a new tool to monitor cooperativity among the switching units. It exhibits a threshold similar to that observed with visible light excitations.