Thickness-tunable magnetic and electronic transport properties of the quasi-two-dimensional van der Waals ferromagnet Co0.27TaS2 with disordered intercalation

Abstract

The intercalation of magnetic elements in nonmagnetic van der Waals (vdW) materials is an effective way to design different (quasi) 2D magnets and produce exotic properties. More specifically, how exactly the intercalator is distributed within the synthetic crystal can also affect the physical properties substantially. In contrast to conventional $3d$ transition-metal intercalates of niobium and tantalum dichalcogenides, which commonly have $2\ifmmode\times\else\texttimes\fi{}2$ or $\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3}$ type ordered intercalation, we report a disordered intercalation of Co atoms between the vdW gaps of $2H$-tantalum disulfide ($2H\text{-Ta}{\mathrm{S}}_{2}$). The obtained quasi-vdW ferromagnet ${\mathrm{Co}}_{0.27}\mathrm{Ta}{\mathrm{S}}_{2}$ shows both perpendicular magnetic anisotropy and thickness-tunable magnetic properties. More interestingly, the temperature dependence of electrical resistivity shows a semiconductorlike behavior, in contrast to the metallic feature of other analogs in this material family. This unexpected phenomenon can be understood through a variable-range hopping mechanism, which is due to highly disordered intercalation. Moreover, ${\mathrm{Co}}_{0.27}\mathrm{Ta}{\mathrm{S}}_{2}$ shows a side-jump scattering dominated anomalous Hall effect, which can also be related to the disordered distribution of Co intercalators.