Electrical read-out of light-induced spin transition in thin film spin crossover/graphene heterostructures

Abstract

Magneto-opto-electronic properties are shown for a hybrid device constructed from a spin crossover (SCO) thin film of the Fe[HB(3,5-(Me)2Pz)3]2 molecular material evaporated over a graphene sensing layer. The principle of...

Nonvolatile Voltage Controlled Molecular Spin-State Switching for Memory Applications

“…The requirements tend to exclude molecular salts and polymers, as neither can be evaporated readily. Yet the approach has been successfully applied to [Fe(1,10-phenanthroline) 2 (NCS) 2 ] (frequently known as Fe(phen) 2 (NCS) 2 ) [38][39][40][41][42][43][44], as illustrated in Figure 2a, [Fe(H 2 B(pz) 2 ) 2 phen] where H 2 B(pz) 2 = dihydrobis(1H-pyrazol-1-yl)borate [45][46][47][48][49][50][51], as illustrated in Figure 2c, [Fe(HB(tz) 3 ) 2 ] (tz = 1,2,4-triazol-1-yl) [52][53][54][55][56], as illustrated in Figure 2d, [Fe(HB(3,5-(CH 3 ) 2 -(pz) 3 ) 2 ], where pz = pyrazolyl [10,[57][58][59][60][61], as illustrated in Figure 2e, [Fe(qnal) 2 ] where qnal = quinoline-naphthaldehyde [62], as illustrated in Figure 2f, [Fe(HB(pz) 3 ) 2 ] where pz = pyrazolyl [11,63], and the molecule that is the focus of this review: [Fe{H 2 B(pz) 2 } 2 (bipy)] where (H 2 B(pz) 2 = bis(hydrido)bis(1H-pyrazol-1-yl)borate, bipy = 2,2 -bipyridine) [13,14,[64][65][66][67][68][69][70]…”

“…Another approach is to use the spin crossover molecular thin film as part of the gate dielectric to a high-mobility graphene device and modulate the conductance in the graphene layer, as demonstrated recently [10,109,110]. This is not regarded here as a competitive approach because of the problems associated with graphene as the channel width shrinks to less than 50 nm [111][112][113][114][115], namely significant increases in effective carrier mass, large edge scattering, and low carrier mobilities, not to mention the problems associated with scaling to large arrays using graphene nanoribbons.…”

“…The successes with organic electronics, combined with indications of success in addressing the complex grand challenge of manipulating magnetically ordered states by electrical means, suggest new approaches and applications to develop novel spintronics. In molecular systems, the spin crossover (SCO) relates to the transition between a low spin (LS) of the metal ion (indeed, diamagnetic state in the case of the Fe 2+ system) to a high-spin (HS) paramagnetic state in 3D transition metal compounds, and for quite some time now, it has been suggested that the spin crossover (SCO) phenomenon has potential applicability in molecular spintronic devices [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. In such device elements, based on the molecular spin state, is very likely that state switching may be accomplished without large current densities or power consumption.…”

“…Such devices work where the voltage control of the molecular spin states leads to nonvolatile conductance changes [13,14]. From these many perspectives of memory devices [1][2][3][4][5][6][7][8][9][10][11][12][13][14] made possible by the molecular spinstate transition, we can construct a list of some of the key elements needed to make a competitive nonvolatile molecular device for memory applications.…”

Transitions photoinduites ultrarapides : un axe émergent pour la photonique

“…L'étude de transitions de phases photoinduites en science des matériaux ouvre une nouvelle voie pour la photonique, car la lumière permet de contrôler diverses fonctions (magnétisme, conductivité optique ou électrique, ferroélectricité,…) sur des échelles de temps ultra-rapides [1][2][3][4]. C'est un axe de recherche très en amont pour la fabrication de futurs composants permettant de moduler la transmission de signaux optiques ou de les convertir en signaux électroniques [5]. Ces transformations de matériaux peuvent être induites par des excitations lumineuses dans diverses gammes spectrales (UV, visible, infrarouge et même THz).…”