23 - Magnetism in zinc oxide (ZnO)

Abstract

Physical properties such as room temperature ferromagnetism in ZnO are induced by defects in the form of Zn vacancies, oxygen vacancies, and interstitial defects. This emerging ferromagnetism in pure metal oxides is commonly referred as d0 ferromagnetism, in which defects are thought to cause electronic band alteration and the establishment of long-range ferromagnetism in these oxides. To improve ferromagnetism in undoped ZnO, one approach is to change the growth environment in the hope that it will change the potential of Zn and O with the occurrence of different defects, which can be accomplished through subsequent synthesis treatments such as annealing in various gaseous atmospheres. Another method is to dope pure ZnO with other metal ions. Many other approaches to magnetism in ZnO have been investigated. As a result, this chapter focuses on understanding magnetism in this wide bandgap semiconductor.