Dependence of the magnetic properties of the dilute magnetic semiconductor Zn_1−xMn_xO nanorods on their Mn doping levels

Highlights: • Mn doped ZnO (Mn 0 mol%–5 mol%) grown by hydrothermal process at 180 °C. • No impurity (Mn) phases could be detected. • A red shift of the UV peak has been towards longer wave lengths. • When electron and hole recombine, a 378 nm UV radiation would be emitted. • The competition between the direct Mn-Mn exchange interactions. • Indirect Mn-O-Mn exchange interaction in the doped Mn ZnO NP's. - Abstract: The effects of Mn doping on the ferromagnetic properties of the dilute magnetic semiconductor Zn_1−xMn_xO nanorods (NR's) having the nominal composit-ions x = 0, 0.01, 0.03, 0.04 and 0.05 grown by a low temperature hydrothermal method are studied. Energy dispersive X-ray (EDX) is used to determine the actual amounts of the elements in each NR's. X-ray diffraction, scanning electron microscopy, photoluminescence and vibrating sample magnetometer measurements are used to observe the effects of the Mn substitution on the properties of the doped ZnO and to relate the changes in the properties to changes in the defect content. It is observed that the saturation magnetization of the Mn ions in the wurtzite structure varies from 0.0210 µ_B/Mn²⁺ to 0.0234 µ_B/Mn²⁺ reaching a high of 0.0251 µ_B/Mn²⁺ as the Mn concentrations is varied from 0.9 to 7.36 atomic%. It is argued that the changes in the saturation magnetization are due to the competition between the direct Mn-Mn exchange interaction and the indirect Mn-O-Mn exchange interaction in the doped Mn ZnO NP's.