THE STUDY OF FERROMAGNETISM IN II-VI DILUTED MAGNETIC SEMICONDUCTORS, Zn1-xMnxO

Abstract Ferromagnetism in II-VI diluted magnetic semiconductor, Zn1−xMnxO is studied. The magnetic behavior of this DMS is studied by using the Heisenberg and the Green’s formalism. The observed ferromagnetism is due to sp - d exchange interactions (RKKY), point defects such as oxygen vacancies, and Zn interstitial. It was also observed that with increasing Mn concentrations up to 4%, the Curie temperature increases and stable ferromagnetic ordering is observed. However, experimenters had found that for Mn concentrations higher than 4% a shift from ferromagnetic to paramagnetic behavior is noticed. This shift is due to the formation of secondary phases in excess of Mn concentrations. The Ferromagnetic behavior of Zn1−xMnxO is detected by theoretical calculation of magnetic quantities by using the Green’s theorem. Ferromagnetic resonance studies also reveal that Zn1−xMnxO nanoparticles exhibit ferromagnetic behavior. The difference in the ferromagnetic properties of the Mn-doped ZnO nanoparticles is primarily attributed to the Mn2+ content. Moreover, magneto-transport properties such as giant magneto resistance and Hall Effect coefficient measurement are found as an additional evidence for the ferromagnetic behaviors of Zn1-xMnxO.