Open AccessHigh temperature annealing treatment on Co doped ZnO bulks
Author(s) -
Peng Xian-De,
Tao Zhu,
Fangwei Wang
Publication year - 2009
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.58.3274
Subject(s) - ferromagnetism , materials science , condensed matter physics , impurity , annealing (glass) , polaron , magnetoresistance , doping , magnetic semiconductor , exchange interaction , scattering , magnetic field , chemistry , metallurgy , physics , electron , organic chemistry , quantum mechanics , optics
Zn0.95Co0.05O Bulk samples were synthesized by solid state reaction method and annealed by different processes. The Zn treated samples show ferromagnetismwhereas the vacuum annealed samples do not show ferromagnetism. The XRD patterns show that there is Co impurity phase in the sample after Zn treatment at 1100℃which is the reason of the ferromagnetism observed. At low temperatureboth the positive and negative magnetoresistance MR effect can be observed for all the samples. We conclude that the s-d exchange_interaction_induced spin-splitting gives rise to positive MR while the formation of bound magnetic polarons and the magnetic field suppressed spin-disorder scattering are responsible for the negative MR behavior under high field.