Transport properties of hydrogenated ZnO microwires

We have studied the magnetoresistance (MR) of hydrogen plasma-treated pure ZnO wires of tens of micrometer diameter at different temperatures. A negative MR of 1% at 8 T applied field is measured for all wires at 4 K, independent of the temperature (300 K … 773 K) used during the hydrogen treatment. However, a positive MR develops, the higher the treatment temperature. The MR can be explained with a semiempirical model taking into account local magnetic moments and thes–dexchange interaction. These results together with field anisotropy in the MR indicate the appearance of magnetic order due to the hydrogen treatment in agreement with recently published reports on the influence of hydrogen in bulk ZnO single crystals. Hydrogen doping may provide a way to trigger defect-induced magnetism in small oxide structures.