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-M = 3 K and the application of a magnetic field results in a cascade of magnetically ordered states for H less than or similar to 1.8 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.