Magnetic and thermodynamic studies on the distorted kagome magnet Pr${}_3$BWO${}_9$

We report specific heat, ac/dc magnetic susceptibility as well as static and pulsed field magnetization studies on the distorted kagome magnet Pr${}_3$BWO${}_9$ down to 0.4~K and up to high magnetic fields. The low-temperature thermodynamic properties are found to be governed by an electronic quasi-doublet ground state; the energy splitting of which amounts to ${\mathrm{\Delta }}_1\simeq 18$ K and exhibits a quadratic field dependence with $g_{\mathrm{e}\mathrm{f}\mathrm{f}}=2.6$. Fitting of the specific heat data implies that the next excited state is strongly gapped at ${\mathrm{\Delta }}_2=430$ K and three-fold degenerate in zero field. Our dc and ac susceptibility studies down to 0.4 K do not detect signatures of distinct spin glass behavior. Pulsed field magnetization measurements up to 60 T confirm the Ising-like paramagnetic nature of the magnetic ground state which is characterized by $m_J=\pm 4$ and the anisotropy energy $E_a\simeq 950$ K.