Ferromagnetism in Mn- and Co-implanted ZnO nanorods

ZnO nanorods with diameters of 15-30 nm were grown on Ag-coated Si substrates by catalyst-driven molecular beam epitaxy and then implanted with Mn+ or Co+ ions to doses of 1-5x 10(16) cm(-2). After subsequent annealing at 700 degreesC for 5 min, the structural properties of the nanorods were unaffected, but they exhibited ferromagnetism that persisted to temperatures of 225-300 K. The coercive fields were less than or equal to100 Oe even at 10 K. The results are similar to those obtained for implantation of Mn+ or Co+ ions in bulk single-crystal ZnO and indicate promise for nanorods for nanoscale spintronic applications. (C) 2003 American Vacuum Society.