부산대학교 도서관

Zn1−xMnxO (x = 0.02, 0.1, and 0.2) nanocrystals were fabricated by using the sol-gel method with various Mn concentrations between x = 0.02 and x = 0.2. Their structural and magnetic characteristics were investigated by using high-resolution X-ray diffraction (HRXRD), scanning electron microscopy(SEM), X-ray photoelectron spectroscopy (XPS), and a superconducting quantum interference device (SQUID). Clear paramagnetic behavior was observed at x = 0.02 and x = 0.1without any secondary phases. Secondary phases, such as ZnMn2O4, started to emerge at x = 0.2,with distinct ferromagnetism being observed between 10 K and room-temperature. The temperature dependence of the field-cooled magnetization agreed well with that of the ZnMn2O4 secondary phase. These results indicate that the ferromagnetism of Mn-doped ZnO can be considered as an extrinsic contribution of magnetic precipitation. In this study, we were able to dope Mn into the Zn sites in ZnO up to a relatively high concentration without a secondary phase, but could not observe intrinsic ferromagnetism over the observed range of Mn concentrations.