Two-dimensional (2D) quantum materials offer a unique platform to explore mesoscopic phenomena driven by interfacial and topological effects. Their tunable electric properties and bidimensional nature enable their integration into sophisticated heterostructures with engineered properties, resulting in the emergence of new exotic phenomena not accessible in other platforms. This has fostered many studies on 2D ferromagnetism, proximity-induced effects, and quantum transport, demonstrating their relevance for fundamental research and future device applications. Here, we review ongoing progress in this lively research field with special emphasis on spin-related phenomena.

The influence of adsorbed oxygen at the first interface of single-crystal Fe(001)/MgO(001)/Fe(001) magnetic tunnel junctions is investigated. Firstly, the adsorption kinetics of O2 on the Fe(001) surface is studied in the monolayer regime by X-ray photoelectrons spectroscopy and scanning tunnelling microscopy experiments. We show that different species exist at the oxidized surface. The tunnel magneto-resistance of oxygen-doped magnetic tunnel junctions is found to decrease but remains large even for oxygen coverages exceeding one monolayer.