Engineering of the magnetic anisotropy of CoB6 monolayer by biaxial tensile strain

•The CoB6 monolayer is metallic ferromagnetism.•The CoB6 monolayer has an in-plane MAE, and maximum value of −0.181 meV/Co at θ=90°.•Applying biaxial tensile strain can enhance the MAE of CoB6 monolayer. Two-dimensional (2D) ferromagnetic material with a sizable magnetic anisotropy energy (MAE) is crucial for exploring and developing the characteristics of spintronic devices. Using first-principles calculations, we study the electronic and magnetic properties of CoB6 monolayer. The CoB6 monolayer shows metallic ferromagnetism and exhibits in-plane magnetic anisotropy. The MAE of CoB6 monolayer is induced by Co atom, its maximum MAE is −0.181 meV/Co at θ=90° ([010] direction), but minimum of −0.157 meV/Co at θ=0° ([100] direction). It is worth noting that MAE of CoB6 monolayer gradually increases when tensile strain gets higher. When tensile strain increases to 8%, the maximum MAE of CoB6 monolayer is estimated to be −0.236 meV/Co at θ=90°, which is enhanced by 50% compared with that of unstrained system. These results may stimulate the development of spintronic nanodevices based on 2D ferromagnetic materials.