In this work, we model the salient magnetic properties of the alloy lamellar ferrimagnetic nanostructures [Formula: see text] between [Formula: see text] semiinfinite leads. We have employed the Ising spin effective field theory (EFT) to compute the reliable magnetic exchange constants for the pure cobalt [Formula: see text] and gadolinium [Formula: see text] materials in complete agreement with their experimental data. The sublattice magnetizations of the [Formula: see text] and [Formula: see text] sites on the individual hcp atomic (0001) planes of the Co–Gd layered nanostructures are computed for each plane and corresponding sites by using the combined EFT and mean field theory (MFT) spin methods. The sublattice magnetizations, effective site magnetic moments, and ferrimagnetic compensation characteristics for the individual hcp atomic planes of the embedded nanostructures, are computed as a function of temperature, and for various stable eutectic concentrations in the range [Formula: see text]. The theoretical results for the sublattice magnetizations and the local magnetic variables of these ultrathin ferrimagnetic lamellar nanostructured systems, between cobalt leads, are necessary for the study of their magnonic transport properties, and eventually their spintronic dynamic computations. The method developed in this work is general and can be applied to comparable magnetic systems nanostructured with other materials.