  With a view to gain an understanding about the alloying tendency of
bimetallic nano alloy clusters of isoelectronics constituents, we studied the
structural and mixing behaviors of Mn$_m$Tc$_n$ alloy clusters with $m+n =$13
for all possible compositions, using first principles electronic structure
calculations. Our study reports a favorable mixing tendency for the alloy
clusters. The average bond lengths of the minimum energy structures show an
overall linear variation with concentrations, indicating a Vegard's law like
variation for the nano alloy clusters, though the optimized structures undergo
a structural transition from a closed and compact structure for the Mn-rich
alloy clusters to an open layered like structure for the Tc-rich alloy
clusters. We figure out a continuous and smooth interplay between hybridization
and magnetization properties of the alloy clusters, which plays a vital role
for the Vegard's law like variation in their average bond lengths.
