The structurally simple complex{Fe^(Ⅱ)[tren(6F-py)_(3)]}(BF_(4))_(2)[tren(6F-py)_(3)=tris(3-aza-4-(6-fluoro-2-pyridyl)-3-butenyl)amine]undergoes an abrupt spin transition(ST)with the critical temperature T↓_(1/2)=24...The structurally simple complex{Fe^(Ⅱ)[tren(6F-py)_(3)]}(BF_(4))_(2)[tren(6F-py)_(3)=tris(3-aza-4-(6-fluoro-2-pyridyl)-3-butenyl)amine]undergoes an abrupt spin transition(ST)with the critical temperature T↓_(1/2)=243 K on cooling and T↑_(1/2)=281 K on heating,with a 38 K wide hysteresis,while the ClO_(4)^(−)congener shows ST spanning the room temperature region at T↓_(1/2)=267 K and T↑_(1/2)=295 K with a 28 K wide hysteresis.Calorimetric data confirm the occurrence of a highly energetic ST process,while multi-temperature single crystal X-ray structural studies identify a concerted symmetry-breaking P2_(1)/n↔P2_(1)/c as the origin of the rare strong cooperativity and the large hysteresis loop.The analysis of the experimental data discloses two distinct interdependent events,namely,the combination of a gradual ST and an induced crystallographic phase transition,which endows the material with strong bistability and makes it an excellent platform for investigating new generations of ST based electronic and spintronic devices.展开更多
基金supported by grant PID2019-106147GB-I00 funded by MCIN/AEI/10.13039/501100011033,Unidad de Excelencia María de Maeztu(CEX2019-000919-M)the Generalitat Valenciana through PROMETEO/2016/147 and EU Framework FET-OPEN project COSMICS(grant agreement 766726)by the grant of the Ministry of Education and Science of Ukraine for perspective development of a scientific direction“Mathematical sciences and natural sciences”at Taras Shevchenko National University of Kyiv.
文摘The structurally simple complex{Fe^(Ⅱ)[tren(6F-py)_(3)]}(BF_(4))_(2)[tren(6F-py)_(3)=tris(3-aza-4-(6-fluoro-2-pyridyl)-3-butenyl)amine]undergoes an abrupt spin transition(ST)with the critical temperature T↓_(1/2)=243 K on cooling and T↑_(1/2)=281 K on heating,with a 38 K wide hysteresis,while the ClO_(4)^(−)congener shows ST spanning the room temperature region at T↓_(1/2)=267 K and T↑_(1/2)=295 K with a 28 K wide hysteresis.Calorimetric data confirm the occurrence of a highly energetic ST process,while multi-temperature single crystal X-ray structural studies identify a concerted symmetry-breaking P2_(1)/n↔P2_(1)/c as the origin of the rare strong cooperativity and the large hysteresis loop.The analysis of the experimental data discloses two distinct interdependent events,namely,the combination of a gradual ST and an induced crystallographic phase transition,which endows the material with strong bistability and makes it an excellent platform for investigating new generations of ST based electronic and spintronic devices.
