Three-dimensional sandglass magnet with non-Kramers ions

Abstract

Magnetic susceptibility, specific heat, and muon spin relaxation ($\ensuremath{\mu}\mathrm{SR}$) measurements have been performed on a synthesized three-dimensional sandglass-type lattice ${\mathrm{Tm}}_{3}{\mathrm{SbO}}_{7}$, where two inequivalent sets of non-Kramers ${\mathrm{Tm}}^{3+}$ ions (${\mathrm{Tm}}_{1}^{3+}$ and ${\mathrm{Tm}}_{2}^{3+})$ show crystal electrical field effect at different temperature ranges. The existence of an ordered or a glassy state down to 0.1 K in zero field is excluded. The low-energy properties of ${\mathrm{Tm}}_{3}{\mathrm{SbO}}_{7}$ are dominated by the lowest non-Kramers quasidoublet of ${\mathrm{Tm}}_{1}^{3+}$, and the energy splitting is regarded as an intrinsic transverse field. Therefore, the low-temperature paramagnetic phenomenon in ${\mathrm{Tm}}_{3}{\mathrm{SbO}}_{7}$ is explained by a transverse field Ising model, which is supported by the quantitative simulation of specific heat data. In addition, the perturbation from ${\mathrm{Tm}}_{2}^{3+}$ may play an important role in accounting for the low temperature spin dynamics behavior observed by $\ensuremath{\mu}\mathrm{SR}$.