Evidence of a magnetic Bose glass in(CH3)2CHNH3Cu(Cl{0.95}Br{0.05})3from neutron diffraction

Abstract

We report the single-crystal study of the bulk magnetization and neutron-scattering measurements on a quantum $S=1/2$ spin ladders system $\text{IPA-Cu}{({\text{Cl}}_{0.95}{\text{Br}}_{0.05})}_{3}$ with quenched disorder. In zero field, the disordered spin liquid phase is preserved as in pure ${\text{IPA-CuCl}}_{3}$. Due to the bond randomness, a different Bose glass phase was directly observed in ${H}_{c}<H<{H}^{\ensuremath{'}}$, which separates the spin liquid phase from the unconventional Bose-Einstein condensation phase. The observed finite value of boson compressibility $(dM/dH)$ and lack of field-induced three-dimensional long-range order are consistent with the theoretical prediction.