Preparation And Physical Properties Of ZnO Based DMS Nanofibers

Zinc oxide (ZnO), a semiconductor with a large exciton binding energy (60 meV) and wide band gap (3.37 eV), has attracted much attention because of its versatile physical properties, such as piezo-electrical, ferro-electrical, electro-optical and acousto-optical characteristics. Diluted magnetic semiconductors (DMS) has attracted significant attention for its potential in providing functionality and enhanced performance in semi-conducting devices, including spin-based field-effect transistors (FETs), spin-polarized lasers, light-emitting diodes (LEDs), nonvolatile magnetic semiconductor memory, and quantum computing. In this paper, Mn and Co-doped ZnO nanofibers have been prepared and their magnetic properties have been studied.Mn-doped ZnO nanofibers have been prepared by sol-gel processing and electrospinning technique. Magnetic property measurements suggested that the Mn-doped ZnO nanofibers exhibited ferromagnetic behavior at 5 K and 50 K, however, paramagnetic behavior at Room temperature. Considering the Curie temperature of Mn3O4 of 44 K, We contributed the paramagnetic propertiy to the competition of ferromagnetic and antimagnetic. The smaller magnetization than that of theoretic values indicated that there were anti-ferromagnetic interactions in the samples.Chain-like Co-doped ZnO nanorods were synthesized by using sol-gel processing and electrospinning technique. The photoluminescence properties of the sample annealed at different atmospheres have also been investigated and strong UV emission was observed. Superconducting quantum interference device magnetometer measurement shows room temperature ferromagnetism and the mechanism of ferromagnetic coupling in Co doped ZnO was also discussed based on a bound magnetic polaron model.