Browsing by Author "Dowben, P. A."

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    The Emergence of the Local Moment Molecular Spin Transistor
    (IOP, 2020-05) Hao, Guanhua; Cheng, Ruihua; Dowben, P. A.; Physics, School of Science
    Local moment molecular systems have now been used as the conduction channel in gated spintronics devices, and some of these three terminal devices might even be considered molecular spin transistors. In these systems, the gate voltage can be used to tune the molecular level alignment, while applied magnetic fields have an influence on the spin state, altering the magnetic properties, and providing insights to the magnetic anisotropy. More recently, the use of molecular spin crossover complexes, as the conduction channel, has led to devices that are both nonvolatile and have functionality at higher temperatures. Indeed, some devices have now been demonstrated to work at room temperature. Here, several molecular transistors, including those claiming to use single molecule magnets (SMM), are reviewed.
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    Nonvolatile voltage controlled molecular spin state switching
    (AIP, 2019) Hao, G.; Mosey, A.; Jiang, X.; Yost, A. J.; Sapkota, K. R.; Wang, G. T.; Zhang, X.; Zhang, J.; N’Diaye, A. T.; Cheng, R.; Xu, X.; Dowben, P. A.; Physics, School of Science
    Voltage-controlled room temperature isothermal reversible spin crossover switching of [Fe{H2B(pz)2}2(bipy)] thin films is demonstrated. This isothermal switching is evident in thin film bilayer structures where the molecular spin crossover film is adjacent to a molecular ferroelectric. The adjacent molecular ferroelectric, either polyvinylidene fluoride hexafluoropropylene or croconic acid (C5H2O5), appears to lock the spin crossover [Fe{H2B(pz)2}2(bipy)] molecular complex largely in the low or high spin state depending on the direction of ferroelectric polarization. In both a planar two terminal diode structure and a transistor structure, the voltage controlled isothermal reversible spin crossover switching of [Fe{H2B(pz)2}2(bipy)] is accompanied by a resistance change and is seen to be nonvolatile, i.e., retained in the absence of an applied electric field. The result appears general, as the voltage controlled nonvolatile switching can be made to work with two different molecular ferroelectrics: croconic acid and polyvinylidene fluoride hexafluoropropylene.