ZnO nanotips, grown on c-Al 2 O 3 and quartz, were implanted variously with 200 keV Fe or Mn ions to a dose level of 5 × 10 16 cm −2 . The magnetic properties of these samples were measured using a superconducting quantum interference device (SQUID) magnetometer. Fe-implanted ZnO nanotips grown on c-Al 2 O 3 showed a coercive field width of 209 Oe and a remanent field of 12% of the saturation magnetization (2.3 × 10 −5 emu) at 300 K for a sample annealed at 700 o C for 20 minutes. The

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... ed and the zero-field-cooled magnetization measurements also showed evidence of ferromagnetism in this sample with an estimated Curie temperature of around 350 K. The Mn-implanted ZnO nanotips grown on c-Al 2 O 3 showed superparamagnetism resulting from the dominance of a spin-glass phase. The ZnO nanotips grown on quartz and implanted with Fe or Mn showed signs of ferromagnetism, but neither was consistent.