Tunable magnetic orders in CePd₂As_2-xP_x

We report the successful synthesis of the polycrystalline compounds CePd₂As_2-xP_x (0 ≤ x ≤ 2) and their physical properties by measuring transport, magnetic and thermodynamic behaviors as a function of temperature and/or magnetic field. Powder x-ray diffraction indicates that CePd₂As_2-xP_x crystallizes in the ThCr₂Si₂-type tetragonal structure. CePd ₂As₂ exhibits a moderate Sommerfeld coefficient of γ ≈ 88 mJ mol^-1 K^-2, and undergoes an antiferromagnetic (AFM) transition at the Néel temperature T_N ≈ 15 K. Upon substituting As with P, the T_N is nearly unchanged up to x ≃ 0.6, while a ferromagnetic (FM) transition develops below T_N for x ≃ 0.4. The Curie temperature T_C increases with increasing x and eventually merges with the AFM transition at x ≃ 0.6. With further increase of x, the system follows typical FM behaviors and its T_C monotonically increases and reaches T_C ≈ 28 K in CePd ₂P₂. Moreover, a metamagnetic transition is observed in the As-rich samples, but vanishes for x ≥ 0.4. Such a tunable magnetic ground state may provide an opportunity to explore the possible quantum critical behavior in CePd₂As_2-xP_x.