Optical and magnetic resonance investigations of Zn1−xMnxO magnetic semiconductors

Zn1−xMnxO crystallites were synthesized by hydrothermal method. X-ray diffraction, UV–Vis absorption spectroscopy, and electron paramagnetic resonance (EPR) spectra confirm the substitution of Zn site by Mn2+ ion. The nonmonotonic variation of band gap exhibits that the short-ranged interactions between the d electrons of Mn and the s and p electrons of the host bands are dominated at lower Mn concentration (x). EPR spectra show that Mn2+ is in exchange interaction at higher x. By using a Curie–Weiss equation on the EPR data, it is found that the dominant magnetic property is antiferromagnetic for higher x, and paramagnetic for lower x.