Spin-flop transition and magnetic phase diagram in CsCo2Se2 revealed by torque and resistivity measurements

Abstract

Abstract The magnetic properties of CsCo2Se2, possessing a ThCr2Si2-structure, are systematically studied by using specific heat, resistivity, and torque measurements. Our results reveal that CsCo2Se2 undergoes a paramagnetic state to antiferromagnetic order at T N ≈ 80 K at zero magnetic field. The T N is nearly independent of the external magnetic field for H ‖ c-axis, and can be suppressed for H ‖ ab-plane below 4 T, above which spin-flop phase transition sets in. At 2 K, the magnetoresistance has a small value of 2.3% for H ‖ c-axis while goes up to 60% for H ‖ ab-plane at 9 T. A hump-like behavior in resistivity was discovered, which was ascribed to a field-induced spin-flop phase transition. The magnetoresistance results suggest that a crossover of spin-flop phase transition occurs at low temperatures in the field range of 2–4 T for H ‖ ab-plane. Furthermore, the magnetic torque results reveal a novel ordered Co spin structure at low temperatures under 6 T for H ‖ ab-plane. Finally, we summarize the magnetic phase diagram of CsCo2Se2 based on resistivity and torque results.