  In this work we explore the interplay between crystallization and glass
transition in different binary mixtures by changing their inter-species
interaction length and also the composition. We find that only those systems
which form bcc crystal in the equimolar mixture and whose global structure for
larger $x_A$ ($x_A=0.6$, where $x_A$ is the mole fraction of the bigger
particles) is a mixed fcc+bcc phase, do not crystallize at this higher
composition. However, the systems whose equimolar structure is a variant of fcc
(NaCl type crystal) and whose global structure at larger $x_A$ is a mixed
NaCl+fcc phase, crystallize easily to this mixed structure. We find that the
stability against crystallization of this "bcc zone" is due to the frustration
between the locally preferred structure (LPS) and the mixed bcc+fcc crystal.
Our study suggests that when the global structure is a mixed crystal where a
single species contributes to both the crystal forms and where the two crystal
forms have large difference in some order parameter related to that species
then this induces frustration between the LPS and the global structure. This
frustration makes the systems good glass former. When $x_A$ is further
increased ($0.70\leq x_A < 0.90$) the systems show a tendency towards mixed fcc
crystal formation. However, the "bcc zone" even for this higher composition is
found to be sitting at the bottom of a V shaped phase diagram formed by two
different variants of the fcc crystal structure, leading to its stability
against crystallization.
