Macroscopic quantum entanglement of oxygen molecules confined into nanopores
Technische Physik, Universität des Saarlandes - 66123 Saarbrücken, Germany
2 Institut Laue-Langevin, BP 156 - 38042 Grenoble, France
Accepted: 12 August 2003
Solid molecular oxygen is a rare example of pure direct-exchange interaction between localized electronic spins S=1. Antiferromagnetic correlations between nearest neighbors exist already in the liquid phase. When solidified, undergoes two magneto-structural phase transitions. The low-temperature phase is long-range ordered with collinear antiferromagnetic alignment of the spins. We performed DC susceptibility measurements of confined into the nanometer-sized pores of silica substrates. At the smallest pore diameters, all solid-solid phase transitions are suppressed. By quantitative investigation of different degrees of filling, we obtain convincing evidence that the major part of the spins is entangled into a collective singlet ground state.
PACS: 75.45.+j – Macroscopic quantum phenomena in magnetic systems / 75.75.+a – Magnetic properties of nanostructures / 75.50.Ee – Antiferromagnetics
© EDP Sciences, 2003