Exchange bias effect of Co3−xFexO4 (x = 0, 0.09, 0.14 and 0.27)
Exchange bias effect of Co3−xFexO4 (x = 0, 0.09, 0.14 and 0.27)
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DOI：
10.1016/j.jallcom.2011.09.077
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发表时间：
2012-02
影响因子：
6.2
通讯作者：
Yue Zhang;Zhi Yang;B. Zhu;Jun Ou-Yang;R. Xiong;Xiaofei Yang;Shi Chen
中科院分区：
文献类型：
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作者：
Yue Zhang;Zhi Yang;B. Zhu;Jun Ou-Yang;R. Xiong;Xiaofei Yang;Shi Chen
采用热分解法制备了Co 3 − xFexO 4（x=0，0.09，0.14和0.27）粉末，并进行了退火处理。随着x的增加，产物的组成经历了从单相化合物Co 3 − xFexO 4到Co 3 − xFexO 4和CoFe 2 O 4共存相的转变，并伴随着铁磁（FM）响应的增强。此外，在Fe ~（3+）掺杂的样品中还观察到了水平负交换偏压（EB）效应。对于x=0.09和0.14的Co 3 − xFexO 4，在10 K下的EB场大于100 Oe，并且当温度高于30 K时EB效应消失，接近反铁磁（AFM）Co 3 O 4的Néel温度。而对于x=0.27的Co 3 − xFexO 4，10 K时的EB场明显减弱，但随着温度升高到200 K，EB效应最终消失。这些结果表明，当x=0.09和0.14时，Co 3 − xFexO 4的电子束效应主要与FM/AFM界面的交换耦合有关，而当x=0.27时，FM和AFM相可能发生退耦.
Co3−xFexO4(x=0, 0.09, 0.14 and 0.27) powders were synthesized by the thermal-decomposition method with annealing treatment. With the increase of x, the composition of the products experiences a transition from the single-phase compound of Co3−xFexO4to the coexisted phases of Co3−xFexO4and CoFe2O4, which is accompanied with the enhancement of the ferromagnetic (FM) response. In addition, the horizontal negative exchange bias (EB) effect was observed in the Fe3+doped samples. For Co3−xFexO4with x=0.09 and 0.14, the EB fields at 10K are larger than 100Oe, and the EB effect disappears as temperature is above 30K, close to the Néel temperature for the antiferromagnetic (AFM) Co3O4. While for Co3−xFexO4with x=0.27, the EB field at 10K weakens clearly, but the EB effect finally disappears as temperature increases to 200K. These results indicate that the EB effect for Co3−xFexO4with x=0.09 and 0.14 are mainly related with the exchange coupling at the FM/AFM interfaces, while for x=0.27, the decoupling of the FM and AFM phases may occur.