title: NMR evidence for the persistence of a spin superlattice beyond the 1/8 magnetization plateau in SrCu2(BO3)_{2}.
abstract: We present 11B NMR studies of the 2D frustrated dimer spin system SrCu2(BO3)_{2} in the field range 27-31 T covering the upper phase boundary of the 1/8 magnetization plateau, identified at 28.4 T. Our data provide a clear evidence that above 28.4 T the spin superlattice of the 1/8 plateau is modified but does not melt even though the magnetization increases. Although this is precisely what is expected for a supersolid phase, the microscopic nature of this new phase is much more complex. We discuss the field-temperature phase diagram on the basis of our NMR data.
authors.affiliation: Institute for Solid State Physics, University of Tokyo, Kashiwanoha, Kashiwa, Chiba 277-8581, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Takigawa
authors.forename: S
authors.initials: S
authors.lastname: Matsubara
authors.forename: M
authors.initials: M
authors.lastname: Horvatić
authors.forename: C
authors.initials: C
authors.lastname: Berthier
authors.forename: H
authors.initials: H
authors.lastname: Kageyama
authors.forename: Y
authors.initials: Y
authors.lastname: Ueda