  We investigate the magnetic properties of a composite comprising of
ferromagnetic Cobalt nanowires embedded in nanoporous anodized alumina
template. We observe unusual increase in, the saturation magnetization and the
coercive field, of the nanowires below 100 K. We also report the appearance of
an unusual exchange bias effect in nanowires below 100 K. We argue our results
can be understood on the basis of a competition between different magnetic
energy scales induced by significant stresses acting on the nanowires at low
temperatures. The composite behaves as an effective medium in which the
magnetic anisotropy of nanowires can be conveniently controlled via stress on
the nanowires.
