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采用固相反应法制备了Zn0.95Co0.05O块体样品,并对其进行了不同方式的退火处理.实验表明在锌气氛中500℃退火的样品表现出铁磁性,而在真空中退火的样品却没有磁性,进一步,在锌气氛中1100℃退火的样品虽然表现出铁磁性,但其铁磁性来源于样品在锌气氛中1100℃退火过程中产生了1%左右的Co金属团簇杂质相.另外,在低温时所有样品都表现出较大的正磁电阻,认为正磁电阻效应是由于s-d电子交换相互作用引起的自旋劈裂造成的,而高场时出现的负磁电阻效应则可能归因于磁场
关键词:
Co掺杂ZnO
X射线衍射
铁磁性
磁电阻 相似文献
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Zn1-xMnxO bulks have been prepared by the solid state reaction method. Zn vapor treatment has been carried out to adjust the carrier concentration. For the Zn treated Zn1-xMnxO bulks, analysis of the temperature dependence of resistance and the field dependence of magnetoresistance demonstrates that the bound magnetic polarons (BMPs) play an important role in the electrical transport behavior. The hopping of BMPs dominates the electrical conduction behavior when temperature is below 170 K. At low temperature,paramagnetic Zn1-xMnxO bulks show a large magnetoresistance effect,which indicates that the large magnetoresistance effect in transition-metal doped ZnO dilute magnetic semiconductors is independent of their magnetic states. 相似文献
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