|
Mn-doped ZnO sample has attracted much interest as material for spintronics, because it shows ferromagnetic properties at room temperature. However, characteristics of Mn-doped ZnO samples are not understood clearly. In this study, the Mn:ZnO films were grown on Si(001) and sapphire(0001) by PLD method at growth temperature of 500〜700°C. ZnO:Mn targets were prepared by mixing Mn metals of 2, 5 and 10 wt% into ZnO powder. X-ray diffraction pattern of target indicated that the target was polycrystalline, but the structure of the thin films was similar to the ZnO structure. The magnetic properties of Mn:ZnO were measured by SQUID magnetometer from 5K to 340 K. The Mn:ZnO samples exhibited ferromagnetic behavior at RT, although paramagnetism contributed mainly to the total magnetic moment of the samples. Magnetization measurements with temperature dependence of the field-cooled (FC) and zero-field-cooled (ZFC) performed in SQUID. Ferromagnetism was shown by the separation in the FC and ZFC curve near RT. Extended X-ray Absorption Fine Structure (EXAFS) measurements were performed using the synchrotron radiation at the beam line of 3C1 of the pohang light source(PLS). EXAFS results show that Mn substitutes into the Zn site and the interactions among Mn can play an important role in ferromagnetism of these samples. |