Highly-tunable ferromagnetism in Cr-doped layered van der Waals NiTe2 crystals with high air stability

Abstract

The discovery of two-dimensional (2D) van der Waals (vdW) ferromagnets has provided a broad platform for the study of spintronics and many novel physical phenomena. However, vdW ferromagnetic crystals generally have a low Curie temperature and poor air stability and their magnetic properties are difficult to modulate. As a layered Dirac semimetal, NiTe₂ has excellent properties such as high electrical conductivity and high air stability. In this work, we report for the first time the introduction of ferromagnetism into NiTe₂ single crystals by doping Cr atoms with the Te-flux method. By controlling the Cr content, the Curie temperature can be tuned from 210 K to 248 K and the saturation magnetic moment from 1.54 emu g⁻¹ to 2.27 emu g⁻¹ which is much higher than the defective magnetism caused by doping. The doped nanosheets still have extremely high air stability, in contrast with most vdW 2D ferromagnet crystals. The results provide opportunities for the study of new highly-tunable, air-stable vdW ferromagnets and their potential applications.