  Spin-dependent transport in a full van der Waals (vdW) giant
magnetoresistance (GMR) junctions with the structure of Fe3GeTe2/XTe2/Fe3GeTe2
(X = Pt, Pd) has been investigated by using first-principles calculations. The
ballistic conductance, magnetoresistance (MR) and resistance-area product (RA)
have been calculated in a current-perpendicular-to-plane (CPP) geometry. A
giant magnetoresistance of around 2000% and RA less than 0.3 {\Omega} {\mu}m2
have been found in the proposed vdW CPP GMR. In addition, the spin-orbit
coupling effect on transport and anisotropy magnetoresistance (AMR) has also
been investigated. The calculated AMR is found to be around 20% in
Fe3GeTe2/trilayer-PdTe2/Fe3GeTe2 CPP GMR. Both GMR and AMR in the proposed vdW
CPP GMR mainly originate from the bulk electronic structure properties of
Fe3GeTe2. This work demonstrates a vdW CPP GMR with superior advantages
including perpendicular magnetic anisotropy, large GMR, low RA as well as
sizable AMR may stimulate future experimental explorations and should be
appealing for their applications in spintronic devices including magnetic
sensor and memory.
