Interference effect in the Landau-Zener tunneling of the   antiferromagnetically coupled dimer of single-molecule magnets
  Two antiferromagnetically coupled tunneling systems is a minimal model exhibiting the effect of quantum-mechanical phase in the Landau-Zener effect. It is shown that the averaged staying probability oscillates vs resonance shift between the two particles, as well as vs sweeping rate. Such a resonance shift can be produced in Mn-4 dimers by the gradient of the magnetic field. 
D. A. Garanin