Magnetic Structure and Metamagnetic Transitions in the van der Waals Antiferromagnet CrPS 4

In 2D magnets, interlayer exchange coupling is generally weak due to the van der Waals layered structure but it still plays a vital role in stabilizing the long‐range magnetic ordering and determining the magnetic properties. Using complementary neutron diffraction, magnetic, and torque measurements, the complete magnetic phase diagram of CrPS 4 crystals is determined. CrPS 4 shows an antiferromagnetic ground state (A‐type) formed by out‐of‐plane ferromagnetic monolayers with interlayer antiferromagnetic coupling along the c axis below T N = 38 K. Due to small magnetic anisotropy energy and weak interlayer coupling, the low‐field metamagnetic transitions in CrPS 4, that is, a spin‐flop transition at ≈0.7 T and a spin‐flip transition from antiferromagnetic to ferromagnetic under a relatively low field of 8 T, can be realized for H ∥ c . Intriguingly, with an inherent in‐plane lattice anisotropy, spin‐flop‐induced moment realignment in CrPS 4 for H ∥ c is parallel to the quasi‐1D chains of CrS 6 octahedra. The peculiar metamagnetic transitions and in‐plane anisotropy make few‐layer CrPS 4 flakes a fascinating platform for studying 2D magnetism and for exploring prototype device applications in spintronics and optoelectronics.