Neutron diffraction of field-induced magnon condensation in the spin-dimerized antiferromagnet Sr3Cr2O8

Abstract

In this work, we investigate the evolution and settling of magnon condensation in the spin-1/2 dimer system ${\mathrm{Sr}}_{3}{\mathrm{Cr}}_{2}{\mathrm{O}}_{8}$ using a combination of magnetostriction in pulsed fields and inelastic neutron scattering in a continuous magnetic field. The magnetic structure in the Bose-Einstein condensation phase was probed by neutron diffraction in pulsed magnetic fields up to 39 T. The magnetic structure in this phase was confirmed to be an $\mathit{XY}$-antiferromagnetic structure validated by irreducible representational analysis. The magnetic phase diagram as a function of an applied magnetic field for this system is presented. Furthermore, zero-field neutron diffraction results indicate that dimerization plays an important role in stabilizing the low-temperature crystal structure.