Signature of Intrinsic High‐Temperature Ferromagnetism in Cobalt‐Doped Zinc Oxide Nanocrystals

Abstract

Nanocrystalline Zn1–xCoxO (x = 0.020, 0.056, and 0.098) powders exhibit intrinsic high-temperature ferromagnetism, as suggested by the well-defined hysteresis loops shown in the figure. The origin of this ferromagnetism is thought to be electron transfer from host Zn 4s↑ states to unfilled dopant Co 3d↓ states (shown in the inset to the figure), which leads to the formation of a spin-split impurity band at the Fermi level in the gap. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2089/2006/c0396_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.