Possible devil's staircase in the Kondo lattice CeSbSe

The temperature- ($T$) magnetic-field ($H$) phase diagram for the tetragonal layered compound CeSbSe is determined from magnetization, specific heat, and electrical resistivity measurements. This system exhibits complex magnetic ordering at ${T}_{\mathrm{M}}=3\phantom{\rule{0.28em}{0ex}}\mathrm{K}$ and the application of a magnetic field results in a cascade of magnetically ordered states for $H\ensuremath{\lesssim}1.8\phantom{\rule{0.28em}{0ex}}\mathrm{T}$ which are characterized by fractional integer size steps: i.e., a possible devil's staircase is observed. Electrical transport measurements show a weak temperature dependence and large residual resistivity which suggest a small charge-carrier density and strong scattering from the $f$ moments. These features reveal Kondo lattice behavior where the $f$ moments are screened incompletely, resulting in a fine balanced magnetic interaction between different Ce neighbors that is mediated by the Ruderman-Kittel-Kasuya-Yosida interaction. This produces the nearly degenerate magnetically ordered states that are accessed under an applied magnetic field.