  Two-dimensional intrinsic ferromagnetic half-metal (HM) are important for the
spintronics. Manipulating the interlayer magnetic coupling of van der Waals
magnetic materials is an important method to control magnetoelectric
properties, which is especially useful for the spintronics. Here, based on
systematical research of CrGeTe3 (CGT) bilayer and multilayers with s of
self-intercalated (SI) Cr atom, we find that self-intercalation can enhance the
interlayer magnetic coupling. The super-exchange interaction still dominates
interlayer magnetic exchange interaction, which results in ferromagnetic
coupling between neighboring vdW layers. CGT bilayer keeps HM with FM order
after Cr self-intercalation, independent of self-intercalated Cr (CrSI) atoms'
concentration. Most importantly, self-intercalated CrGeTe3 (SI-CGT) bilayers
show ferromagnetic HM, independent of stacking orders. Moreover, SI-CGT
multilayers keep FM order, independent of films' thickness. However, SI-CGT
multilayers transform from HM into normal spin-polarized metal, as the states
at the Fermi-level increases. Moreover, magnetic anisotropy energy (MAE) of
SI-CGT-AA and SI-CGT-AB are -0.160 and -0.42 meV/.f.u., which are modulated by
CrSI atoms. The MAE of SI-CGT-AA and SI-CGT-AB are different, as the
hybridization interaction between Cr's d orbitals is different. SI-CGT
multilayers' magnetic easy axis (EA) switches from [001] of CGT to [100]
direction, independent of stacking orders. It origins that MAE mainly
contributed by hybridization between Te atoms' px and py, py and pz orbitals is
obvious weakened as CrSI is introduced. SI-CGT multilayers show good dynamical,
thermal, and magnetic stability at 300 and 500 K. These findings find a
promising way to manipulate interlayer exchange interaction and magnetoelectric
properties of CGT multilayers and other vdW magnets.
