  The V-Ti alloys are promising materials as alternate to the commercial
Nb-based superconductors for high current-high magnetic field applications.
However, the critical current density (J_c) of these alloys are somewhat low
due to their low grain-boundary density. We show here that grain refinement of
the V-Ti alloys and enhancement of the J_c can be achieved by the addition of
Gd into the system, which precipitates as clusters along the grain boundaries.
Both the J_c and the pinning force density (F_P) increase with the increasing
Gd content up to 1 at. % Gd, where they are more than 20 times higher than
those of the parent V_0.60Ti_0.40 alloy. Introduction of Gd into the system
also leads to ferromagnetic (FM) correlations, and the alloys containing more
than 0.5 at. % Gd exhibit spontaneous magnetization. In spite of the FM
correlations, the superconducting transition temperature increases slightly
with Gd-addition.
