Structural, optical and magnetic properties of polycrystalline ceramics

Structural, optical and magnetic properties of polycrystalline Zn1−xMnxO ceramics are studied. X-ray diffraction patterns reveal that Zn1−xMnxO samples with x ≤ 0.04 are single phase in the wurtzite structure. The increase in Mn concentration with x > 0.04 leads to the formation of tetragonal ZnMn2O4 spinel. This changes the peak position and intensity of ultraviolet emission centered at about 379 nm. Under an excitation wavelength of 488 nm, we have observed luminescence emission peaked at about 650 nm, which is related to electronic transitions of Mn2+ ions in the ZnO crystal field. An incorporation of Mn dopants into the ZnO host lattice and the formation of ZnMn2O4 are also confirmed by Raman scattering spectroscopy, based on the feature of additional modes. Electron spin resonance study exhibits the existence of Mn2+ and Mn3+ ions in Zn1−xMnxO. The variation of Mn content ( x ) changes the concentration of these ions, and thus influences the resonant parameters.