Abstract: The massive advancements in performance from the first computing machines to the current electronic devices are mainly due to the extreme miniaturization of their active components. At present, further downscaling represents an enormous technological challenge, as the size of the devices is reaching the ultimate limit of the molecular and atomic scale. The evolution of a novel discipline, known as molecular spintronics, is contributing to develop new concepts and tools to control matter at the single-molecule scale and to manipulate spins and charges in electronic devices containing one or more molecules. In this framework, single-molecule magnets are expected to be suitable candidates as building blocks for molecular spintronic devices. One of the most interesting applications is the realization of electronic circuits addressing individual molecules in the three-terminal configuration, the so-called single-molecule transistors. Groundbreaking results have been achieved in this field, including the electrical read-out and manipulation of an individual nuclear spin.
In this talk, the use of graphene as a convenient platform to fabricate molecular-scale electrodes will be discussed. A feedback-controlled electroburning (EB) procedure was employed to open nanometer-sized gaps in graphene junctions suitable to contact single molecules. A systematic characterization of the EB performed on different types of graphene devices and in different environmental conditions will be provided. By means of this EB procedure, three-terminal molecular devices were prepared in which a Tb-based single-molecule magnet (TbPc2 or Tb2Pc3) is embedded between two nm-sized graphene electrodes. The low-temperature operation of these molecular spin transistors will be examined, with a particular focus on the detection mechanism of the Tb electronic spin reversal during the sweeping of an external magnetic field.