NMR evidence for the persistence of a spin superlattice beyond the 1/8 magnetization plateau in SrCu2(BO3)_{2}.
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.
Takigawa
M
M
Institute for Solid State Physics, University of Tokyo, Kashiwanoha, Kashiwa, Chiba 277-8581, Japan.
Matsubara
S
S
Horvatić
M
M
Berthier
C
C
Kageyama
H
H
Ueda
Y
Y