F-Center-Mediated Ferromagnetic Ordering in K-Doped ZnO

Diluted magnetic semiconducting particles of K-doped ZnO synthesized by solution combustion technique are discussed here. The structural, optical, and magnetic properties are examined. The incorporation of K into ZnO lattice is understood from the varying lattice parameters. Consequently, there is shrinkage in the band gap of K-doped ZnO. The strain present in the samples is understood from the Fourier transform (FT)-Raman analysis. The photoluminescence (PL) spectra validate the band gap obtained from ultraviolet-visible-near infrared spectrophotometer (UV-Vis-NIR) study. Besides a high intense blue emission along with an impuissant green emission due to zinc interstitials and oxygen, vacancies are detected from PL spectra. The hysteresis loop obtained from vibrating sample magnetometer (VSM) limpidly expounds the ferromagnetic ordering of the samples. The ferromagnetic nature is attributed to the oxygen vacancies that form F-center that is responsible for magnetism in oxide semiconductors.