Reliability and storage capacity: a compromise illustrated in the two-step spin-crossover system [Fe(bapbpy)(NCS)(2)].
The design of bistable magnetic systems should enable the storage of information by manipulation of the spin degrees of freedom. However, such a strategy relies on the preparation of target objects, whose environment must be controlled to favor a hysteretic behavior. Here, we report the successful modeling of a highly cooperative two-step spin-crossover iron(II) compound, [Fe(bapbpy)(NCS)(2)]. The magnetic susceptibility measurements and low- and high-temperature hysteretic cycles reflect the presence of an intermediate phase, which controls the memory-storage capacity of this material. It is shown that the hysteresis loop widths can be traced theoretically by evaluating the electrostatic contributions between the transiting units. Despite the apparent reduction of intermolecular interactions upon cooling, it is suggested that the enhanced fluctuations of the Madelung field are responsible for the observed hysteresis width changes. This counterintuitive scenario makes the preparation of information storage devices an even more challenging task, where theoretical inspections are very insightful.
Laboratoire de Chimie, Ecole Normale Supérieure de Lyon, CNRS, Université de Lyon, 46 allée d'Italie, 69364 Lyon Cedex 07, France.
Mikael
M
Kepenekian
José Sánchez
JS
Costa
Boris
B
Le Guennic
Pascale
P
Maldivi
Sylvestre
S
Bonnet
Jan
J
Reedijk
Patrick
P
Gamez
Vincent
V
Robert