Composition-tuned Co(n)Si nanowires: location-selective simultaneous growth along temperature gradient.

We report the simultaneous and selective synthesis of single-crystalline Co(n)Si NWs (n = 1-3) and their corresponding crystal structures--simple cubic (CoSi), orthorhombic (Co(2)Si), and face-centered cubic (Co(3)Si)--following a composition change. Co(n)Si NWs were synthesized by placing the sapphire substrates along a temperature gradient. The synthetic process is a successful demonstration of tuning the chemical composition in Co(n)Si NWs. The synthesis and detailed crystal structure of single-crystalline Co(2)Si and Co(3)Si are reported for the first time including the bulk and the nanostructure phases. The electrical and magnetic properties of Co(2)Si NWs are investigated and compared with those of CoSi NWs.