Molecular based spintronic devices offer great potential for future energy-efficient information technology as they combine ultimately small size, high-speed operation, and low-power consumption. Recent developments in combining atom-by-atom assembly with spin-sensitive imaging and characterization at the atomic level have led to a first prototype of an all-spin atomic-scale logic device, but the very low working temperature limits its application. Here, we show that a more stable spintronic device could be achieved using tailored Co-Salophene based molecular building blocks, combined with in situ electrospray deposition under ultrahigh vacuum conditions as well as control of the surface-confined molecular assembly at the nanometer scale. In particular, we describe the tools to build a molecular, strongly bonded device structure from paramagnetic molecular building blocks including spin-wires, gates, and tails. Such molecular device concepts offer the advantage of inherent parallel fabrication based on molecular self-assembly as well as an order of magnitude higher operation temperatures due to enhanced energy scales of covalent through-bond linkage of basic molecular units compared to substrate-mediated coupling schemes employing indirect exchange coupling between individual adsorbed magnetic atoms on surfaces.

Molecular spintronics is currently attracting a lot of attention due to its great advantages over traditional electronics. A variety of self-assembled molecule-based devices are under development, but studies regarding the reliability of the growth process remain rare. Here, we present a method to control the length of molecular spintronic chains and to make their terminations chemically inert, thereby suppressing uncontrolled coupling to surface defects. The temperature evolution of chain formation was followed by X-ray photoelectron spectroscopy to determine optimal growth conditions. The final structures of the chains were then studied, using scanning tunneling microscopy, as a function of oligomerization conditions. We find that short chains are readily synthesized with high yields and that long chains, even exceeding 70mers, can be realized under optimized growth parameters, albeit with reduced yields.

Advances in molecular spintronics rely on the in-depth characterization of the molecular building blocks in terms of their electronic and, more importantly, magnetic properties. For this purpose, inert substrates that interact only weakly with adsorbed molecules are required in order to preserve their electronic states. Here, we investigate the magnetic-field response of a single paramagnetic 5,5'-dibromosalophenatocobalt(II) (CoSal) molecule adsorbed on a weakly interacting magnetic substrate, namely Fe-intercalated graphene (GR/Fe) grown on Ir(111), by using spin-polarized scanning tunneling microscopy and spectroscopy (SP-STM/STS). We have obtained local magnetization curves, spin-dependent tunneling spectra, and spatial maps of magnetic asymmetry for a single CoSal molecule, revealing its magnetic properties and coupling to the local environment. The distinct magnetic behavior of the Co-metal center is found to rely strictly on its position relative to the GR/Fe moiré structure, which determines the level of hybridization between the GR/Fe surface π-system, the molecular ligand π-orbitals and the molecular Co-ion d-orbital.Molecular-based systems are promising candidates for nanospintronic devices, the main examples being single molecular magnets (SMMs) []. In most of these studies the molecules' orbitals were strongly hybridized with the substrates' electronic states [Schwöbel, 2012,

The magnetic structure of a monolayer-thick GdAu 2 surface alloy on Au(111) has been investigated down to the atomic level by spin-polarized scanning tunneling microscopy. Spin-resolved tunneling spectroscopy combined with density-functional theory calculations reveal the local spin polarization of both Gd and Au atomic sites within the surface alloy. Moreover, the impact of dislocation lines on the atomic-scale magnetic structure as well as on the local coercive field strength is demonstrated.

On-surface metalation provides a tool to vary magnetic and electronic properties of metal−organic complexes and produces clean samples of the desired product. We used this technique to metalate 5,5′-dibromosalophene with the 3d transition metals Co, Fe, and Cr on Co-intercalated graphene grown on Ir(111). The metalation process was investigated by X-ray photoelectron spectroscopy (XPS). The electronic structure of the obtained salophene complexes was investigated using a combination of scanning tunneling microscopy and spectroscopy with density functional theory calculations. XPS data show that deposition of the transition metals at 398 K causes the metal atoms to interact with the molecules, while higher temperatures are needed to complete the reaction. Furthermore, we are able to distinguish the three different metal−organic complexes by their electronic structure.