2007 journal article

The effect of oxygen annealing on ZnO : Cu and ZnO :(Cu,Al) diluted magnetic semiconductors

JOURNAL OF PHYSICS D-APPLIED PHYSICS, 40(24), 7606–7613.

By: D. Chakraborti n, G. Trichy n, J. Prater n & J. Narayan n 

co-author countries: United States of America 🇺🇸
Source: Web Of Science
Added: August 6, 2018

Here we report a systematic study of magnetic, electronic and microstructural properties of Cu-doped and Cu and Al codoped ZnO thin films, grown epitaxially on a (0 0 0 1) sapphire substrate by the pulsed laser deposition technique. The films were annealed in oxygen at high temperature (600 °C) and their properties were compared with the as deposited films in order to study the role of defects like oxygen vacancies on the ferromagnetic properties. The doping of ZnO : Cu specimens with Al increased the carrier concentration by three orders of magnitude (from 1017 to 1020 cm−3) without altering the ferromagnetic ordering. On the other hand, a reduction in oxygen vacancies concentration brought about by high temperature annealing in oxygen had a large detrimental effect on ferromagnetism. These results tend to eliminate a free carrier mediated mechanism and point towards a defect mediated mechanism, such as a bound-magnetic-polaron mediated exchange, as being responsible for stabilizing long-range ferromagnetic ordering in these systems.