Molecular Photomagnets

Phase diagrams and free-energy landscapes for model spin-crossover materials with antiferromagnetic-like nearest-neighbor and ferromagnetic-like long-range interactions

“…Molecules in the HS state have larger volume and higher effective degeneracy than those in the LS state [1][2][3][4][5][6][7][8]. Due to its higher degeneracy, crystals of such molecules can be brought into a majority excited HS state by increasing temperature, changing pressure or magnetic field, electrochemical stimuli, or exposure to light [4,6,[9][10][11][12][13][14][15][16][17]. The size difference between the HS and LS molecules causes local elastic distortions that lead to effective long-range elastic interactions mediated by the macroscopic strain field [5,18,19].…”

“…These intermolecular interactions may cause first-order phase transitions that can render the HS state metastable and lead to hysteresis when exposed to time-varying fields [11,20]. In the case of optical excitation into the metastable phase, this phenomenon is known as light-induced excited spin trapping (LIESST) [9,11,17]. The metastable properties in combination with the SC materials' sensitivity to a wide range of external stimuli make them promising candidates for applications such as switches, displays, memory devices, sensors, and actuators [13,15,21,22].…”