Controlling Spin Orientation and Metamagnetic Transitions in Anisotropic van der Waals Antiferromagnet CrPS4 by Hydrostatic Pressure

Controlling the phases of matter is a central task in condensed matter physics and materials science. In 2D magnets, manipulating spin orientation is of great significance in the context of the Mermin-Wagner theorem. Herein, a systematic study of temperature- and pressure-dependent magnetic properties up to 1 GPa in van der Waals CrPS4 is reported. Owing to the temperature-dependent change of the magnetic anisotropy energy, the material undergoes a first-order spin reorientation transition with magnetic moments realigning from being almost parallel with the c axis in the ac plane to the quasi-1D chains of CrS6 octahedra along the b axis upon heating. The spin reorientation temperature is suppressed after applying pressure, shifting the high-temperature phase to lower temperatures with the emergence of spin-flop transitions under magnetic fields applied along the b axis. The saturation field increases with pressure, indicating the enhancement of interlayer antiferromagnetic coupling. However, the Neel temperature is slightly reduced, which is ascribed to the suppression of intralayer ferromagnetic coupling. The work demonstrates the control of spin orientation and metamagnetic transitions in layered antiferromagnets, which may provide new perspectives for exploring 2D magnetism and related spintronic devices.