Synthesis and characterization of self organized SiO2 nano pillar with MnO as the magnetic tip.

Self organized SiO2 nanopillar with MnO tip have been synthesized over Si substrate by annealing the substrate after putting drop of MnCl2 (in C2H5OH and H2O) over its surface. The controlled growth of nanopillars has been achieved by annealing as sampled Si substrate at 940 oC in Ar and H2 gas environment (Ar =150 ml/min, H2 =75 ml/min) for 2 hour. Synthesized nanopillars are vertical over the silicon substrate. Energy dispersive x-ray (EDX) analysis shows that the pillar structures are formed of Si, O and Mn, wherein the catalyst Mn has been found in the form of MnO at the tip of the nanopillar, inferred from the EDX, X-ray magnetic-circular dichroism (XMCD) and near edge x-ray fine structure (NEXAFS) analysis. HETEM analysis shows the tip as well as the pillars are amorphous. The MnO tip has magnetic nature as concluded by XMCD studies of the samples. Spectral features of Mn K-edge EXAFS reveals that Mn is in 2+ state and coordinated in tetrahedral symmetry.