Ferromagnetism and anomalous Hall effect in Mn-doped ZnO thin films grown by reactive sputtering

In this work, the growth of Mn-doped p-type ZnO thin film by reactive sputtering and their conduction type dependent magnetic properties are reported. Mn-doped ZnO thin films are deposited on SiO₂/Si substrates by reactive magnetron sputtering at 500°C and P is used as p-type dopant in Mn-doped ZnO via ZnO target mixed with 10wt% P₂O₅. Rapid thermal annealing above 500°C is also done. A p-type conduction with the highest concentration of 6.7 × 10¹⁸ cm^-3 in Zn_0.99Mn_0.01O:P is accomplished by annealing at 800°C under N₂ ambient. The p-type Zn_0.99Mn_0.01O:P film exhibits room temperature ferromagnetism with saturation magnetization of 0.301 emu/cm³ and coercive field of 60 Oe in contrast with paramagnetism in n-type Zn_0.99Mn_0.01O:P. In addition, an anomalous Hall effect is observed at room temperature in p-type films. This result manifests the intrinsic nature of ferromagnetism, hole-induced ferromagnetism, in p-type Zn_0.99Mn_0.01O:P, and represents the possible realization of diluted magnetic semiconductor spintronic devices operable at room temperature.