Dresden 2017 – wissenschaftliches Programm
MA 15.11: Vortrag
Montag, 20. März 2017, 17:45–18:00, HSZ 403
Magnetic and structural properties in the spin-dimer system Ba0.1Sr2.9Cr2O8 — •Alsu Gazizulina1, Diana Lucia Quintero Castro2, and Andreas Schilling1 — 1Physik-Institut of University of Zurich, Zurich, Switzerland — 2Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
Sr3Cr2O8 and Ba3Cr2O8 are two insulating dimerizad antiferromagnets with the magnetic ions, Cr 5+, that lie on hexagonal bilayers with strong intradimer antiferromagnetic interaction. This leads to a singlet ground state and gapped triplet states. Intradimer interaction constant J0 strongly depends on the stoichiometry.
We report on the change of the structural and magnetic properties of a spin-dimer system, Sr3Cr2O8, by introducing chemical disorder. Two large single crystal of Ba(3-x)Sr(x)Cr2O8 with x=2.9 and x=2.8 have been grown in a four-mirror type optical floating-zone furnace. By performing magnetization, heat-capacity measurements we have studied structural and magnetic properties of these compounds. Our inelastic neutron scattering measurements of spin-dimer compound Ba0.1Sr2.9Cr2O8 determine the interaction constants and the spin gap. The intradimer interaction constant is found to be J0=5.327(1) meV, that about 8% smaller than for pure Sr3Cr2O8 compound. Spin gap is decreasing about 6% with introducing chemical disorder.