Effect of hydrostatic pressure on ferromagnetism in two-dimensional CrI₃

Abstract

We have investigated the magnetic properties of the highly anisotropic layered ferromagnetic semiconductor CrI₃ under hydrostatic pressure with the magnetic field along the easy axis of magnetization. At ambient pressure, CrI₃ undergoes a second-order paramagnetic-to-ferromagnetic phase transition at TC=60.4 K. TC is found to increase sublinearly from 60.4 to 64.9 K as pressure increases from 0 to 1.0 GPa. With the increase in pressure, the transition becomes sharper while magnetization at low field decreases monotonically due to a decrease in magnetocrystalline anisotropy. The weak low-field anomaly at around 48 K, resulting from two-step magnetic ordering, also shifts toward higher temperatures with increasing pressure. The observed increase in TC and the decrease in magnetization could originate from a change in coupling between the layers and the Cr-I-Cr bond angle with pressure.