Doping and defect engineering induced extremely high magnetization and large coercivity in Co doped MoTe2

Abstract

Magnetism in layered two dimensional materials has attracted extensive interest. In this work, a variety of concentrations of Co dopants (1, 2 and 4 at.%) were doped into MoTe2 single crystal by ion implantation. Magnetic results indicate that pure MoTe2 displays a diamagnetic behavior. A small amount of Co doping induces a very high saturation magnetization. 4 % Co doping exhibits a saturation magnetization as high as 2231 emu/cm3, higher than pure metallic Fe (1958 emu/cm3). In addition, an outsized coercivity of 11 kOe was also detected in the 2 at.% Co doped MoTe2 sample, which may be a consequence of doping-induced defects in the lattice structure, stress, anisotropic geometry of Co-Te ions and pinning effects by the defects in-between the ions. First principles density functional theory calculations reveal that doping-induced structural defects, including substitutional and interstitial Co, nanoholes as well as interstitial Mo, are responsible for the high magnetization.