Magnetic Properties of Electrically Contacted Fe$_{4}$ Molecular Magnets

Single molecule magnets (SMMs) are often large and fragile molecules. This poses challenges for the construction of SMM based spintronics. Device geometries with two electronic leads contacting a molecule may be explored via scanning tunneling microscopy (STM). The Fe$_{4}$ molecule [1] stands out as a robust, thermally evaporable SMM, making it ideal for such an experiment. Here we present the first STM investigations of individual Fe$_{4}$ molecules thermally evaporated onto a monolayer of Cu$_{2}$N on a Cu (100) crystal. Using inelastic electron tunneling spectroscopy (IETS), spin excitations in single Fe$_{4}$ molecules can be detected at meV energies. Analysis using a Spin Hamiltonian [2] allows extraction of magnetic properties of individual Fe$_{4}$ molecules, and investigation of the influence of the electronic leads. The tip and sample induce small changes in the magnetic properties of Fe$_{4}$ molecules, making Fe$_{4}$ a promising candidate for the development of spintronics devices based on SMMs. \\[4pt] [1] Nature 468, 417 (2010). [2] Nano Letters 12, 518 (2012).