  We present extensive first principles density functional theory (DFT)
calculations dedicated to analyze the magnetic and electronic properties of
small V$_{n}$ clusters (n=1,2,3,4,5,6) embedded in a Cu fcc matrix. We consider
different cluster structures such as: i) a single V impurity, ii) several
V$_{2}$ dimers having different interatomic distance and varying local atomic
environment, iii) V$_{3}$ and iv) V$_{4}$ clusters for which we assume compact
as well as 2- and 1-dimensional atomic configurations and finally, in the case
of the v) V$_{5}$ and vi) V$_{6}$ structures we consider a square pyramid and a
square bipyramid together with linear arrays, respectively. In all cases, the V
atoms are embedded as substitutional impurities in the Cu network. In general,
and as in the free standing case, we have found that the V clusters tend to
form compact atomic arrays within the cooper matrix. Our calculated non
spin-polarized density of states at the V sites shows a complex peaked
structure around the Fermi level that strongly changes as a function of both
the interatomic distance and local atomic environment, a result that
anticipates a non trivial magnetic behavior. In fact, our DFT calculations
reveal, in each one of our clusters systems, the existence of different
magnetic solutions (ferromagnetic, ferrimagnetic, and antiferromagnetic) with
very small energy differences among them, a result that could lead to the
existence of complex finite-temperature magnetic properties. Finally, we
compare our results with recent experimental measurements.
