Complex magnetic behavior of the Ce sawtooth chains in CeRhSn 2

Conflicting reports exist on the ground state of the intermetallic compound CeRhSn 2 . This can be rooted in the sawtoothlike arrangement of two inequivalent Ce sites in the unit cell, which suggests potential geometric magnetic frustration. To resolve these conflicting reports, we conducted a comprehensive study on high-quality single crystals of CeRhSn 2 by means of magnetization ( M ), specific heat ( C p / T ), and resistivity ( ρ ). The system exhibits strong magnetic anisotropy, confirming the b axis as the easy magnetic axis. We establish three successive transitions: an antiferromagnetic order at T N = 3.65 K , a first-order ferromagnetic (FM) order at T C = 1.7 K and final transition, at T = 1.5 K . The transition temperatures are highly field-directional dependent: in a magnetic field, the lowest transition is immediately suppressed while H ∥ b rapidly merges T C and T N into a single second-order transition. Conversely, H ∥ c suppresses the FM order and reduces T N . Additional calculations affirm the FM ground state of CeRhSn 2 . The observation of an enhancement of the Sommerfeld coefficient ( γ = 76.5 mJ/mol K 2 ) may arise from geometric frustration, but it is most consistently attributed to weak Kondo hybridization as frustration cannot be conclusively established through our data.