Publications [#302511] of Sara Haravifard

Papers Published
  1. Haravifard, S; Banerjee, A; van Wezel, J; Silevitch, DM; dos Santos, AM; Lang, JC; Kermarrec, E; Srajer, G; Gaulin, BD; Molaison, JJ; Dabkowska, HA; Rosenbaum, TF, Emergence of long-range order in sheets of magnetic dimers., Proceedings of the National Academy of Sciences of the United States of America, vol. 111 no. 40 (October, 2014), pp. 14372-14377 [doi] .

    Quantum spins placed on the corners of a square lattice can dimerize and form singlets, which then can be transformed into a magnetic state as the interactions between dimers increase beyond threshold. This is a strictly 2D transition in theory, but real-world materials often need the third dimension to stabilize long-range order. We use high pressures to convert sheets of Cu(2+) spin 1/2 dimers from local singlets to global antiferromagnet in the model system SrCu2(BO3)2. Single-crystal neutron diffraction measurements at pressures above 5 GPa provide a direct signature of the antiferromagnetic ordered state, whereas high-resolution neutron powder and X-ray diffraction at commensurate pressures reveal a tilting of the Cu spins out of the plane with a critical exponent characteristic of 3D transitions. The addition of anisotropic, interplane, spin-orbit terms in the venerable Shastry-Sutherland Hamiltonian accounts for the influence of the third dimension.