2003/01/27 by H. Tsujii, Tsujii, H., R. C. Rotundu +11
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Iron-based superconductors research #Physics of Superconductivity and Magnetism #cond-mat.stat-mech #cond-mat.str-el
paper · pdf · doi:10.48550/arxiv.cond-mat/0301509
v2: minor typographical corrections. 4 pages, 2 Postscript figures
arxiv created 2003/01/31 · arxiv updated 2009/11/30
We characterize the field-induced magnetic phases of SrCu2(BO3)2, a frustrated spin-1/2 Heisenberg antiferromagnet in the two-dimensional Shastry-Sutherland lattice, using specific heat in magnetic fields up to 33 T. We find that the spin gap persists above the expected critical field Hc = Delta/g*muB of 21 T despite the appearance of magnetic moment in the ground state. At the magnetization plateau at 1/8 of the saturation, the Sz = +1 triplets that carry the magnetization of the ground state are observed to form a two-dimensional spin gas of massive bosons. A spin gas consisting of the same number of massive particles continues to completely dominate the specific heat in the field region above the plateau, although the magnetization increases with increasing field. Ordering is observed at a temperature immediately below the spin-gas regime.