Ferromagnetism in ZnO Nanocrystals: Doping and Surface Chemistry

Room temperature ferromagnetic ordering is observed in chemically grown ZnO nanocrystals. Nanocrystals are simultaneously capped by two different organic molecules inducing p-type and n-type defects. A saturation magnetization of 0.008 emu/g is achieved at 300 K. Incorporation of Mn2+ ions at substi...

Full description

Saved in:
Bibliographic Details
Published in:Journal of physical chemistry. C 2010-01, Vol.114 (3), p.1451-1459
Main Authors: Inamdar, Darshana Y, Lad, Amit D, Pathak, Arjun K, Dubenko, Igor, Ali, Naushad, Mahamuni, Shailaja
Format: Article
Language:English
Subjects:
C: Nanops and Nanostructures
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Room temperature ferromagnetic ordering is observed in chemically grown ZnO nanocrystals. Nanocrystals are simultaneously capped by two different organic molecules inducing p-type and n-type defects. A saturation magnetization of 0.008 emu/g is achieved at 300 K. Incorporation of Mn2+ ions at substitutional sites in nanocrystals gives rise higher saturation magnetic moment at lower doping level. ZnO nanocrystals codoped with Mn2+ and Co2+ and prepared under identical conditions revealed an increase in saturation magnetization. However, the saturation magnetic moment remains lower than that obtained for Co2+-doped ZnO nanocrystals prepared by the same method. An increase in saturation magnetization was invariably associated with quenching of photoluminescence emission. These findings reaffirm that magnetism in nanocrystals is a defect induced phenomenon that can be controlled by choice of capping agent as well as incorporation of the transition metal impurity. Magnetization as a function of temperature [M(T)] curve is discussed in view of available reports on the global exchange mechanism in these ferromagnetic nanocrystals.
ISSN:1932-7447
1932-7455
DOI:10.1021/jp909053f