Magnetic spin clusters of O2 confined in a slit-shaped graphitic nanosapce at low temperature

The magnetic behavior of O2 molecules confined in slit-shaped graphitic micropores at different coverages was examined as a function of the slit pore width from 0.75 to 1.45 nm at 1.7–100 K. The adsorbed O2 at low coverages showed paramagnetism without any obvious magnetic transition, which was quite close to the magnetism of bulk gaseous oxygen. An antiferromagnetic behavior appeared with an increase in ϱ. This behavior was caused by cluster formation, rather than by the formation of 2D lattices or bulk solid phases. The O2 submonolayer in the micropore showed different magnetic behavior depending on the pore width.