High-field magnetization process in theS=1quantum spin systemBa3Mn2O8

Abstract

${\mathrm{Ba}}_{3}{\mathrm{Mn}}_{2}{\mathrm{O}}_{8}$ is an $S=1$ coupled spin dimer system with a gapped ground state. The magnetization process of this compound has been measured up to 50 T at 0.65 K. Magnetization plateaus were clearly observed at zero and at half of the saturation magnetization. The excitation gap was estimated as $\ensuremath{\Delta}{/k}_{\mathrm{B}}=12.3 \mathrm{K}.$ The magnetization curve was analyzed and the spin structure in the field-induced ordered state was discussed within the framework of the mean-field approximation.