Enhancement of Interparticle Exchange Coupling in CoFe2O4/CoFe2 Composite Nanoceramics Via Spark Plasma Sintering Technology
Enhancement of Interparticle Exchange Coupling in CoFe2O4/CoFe2 Composite Nanoceramics Via Spark Plasma Sintering Technology
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DOI：
10.1111/jace.12582
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发表时间：
2013-12
影响因子：
3.9
通讯作者：
Yue Zhang;R. Xiong;Zhi Yang;Wei Yu;B. Zhu;Shi Chen;Xiaofei Yang
中科院分区：
文献类型：
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作者：
Yue Zhang;R. Xiong;Zhi Yang;Wei Yu;B. Zhu;Shi Chen;Xiaofei Yang
采用放电等离子烧结技术，在还原气氛中加热CoFe 2 O 4粉末，将还原反应产物在350°C下烧结，制备了CoFe 2 O 4、CoFe 2和少量FeO复合的粉末和纳米铈。在300°C ~ 400°C范围内，随着加热温度的升高，CoFe_2：CoFe_2 O_4的摩尔比增大，磁性参数变化较大，磁滞回线的阶跃和负汉克尔图证实了在颗粒间的相互作用中，偶极相互作用占主导地位.然而，在纳米铈中，当烧结温度升高到500°C和650°C时，发现交换耦合显著增强，这由Henkel图的正性和磁滞回线的单相样式两者证实。
Powders and nanoceramics composed of composites of CoFe2O4, CoFe2, and a small amount of FeO were prepared by heating CoFe2O4 powder in reducing atmosphere and by sintering the product of reducing reaction at 350°C via spark plasma sintering technology. In the powders, increase in the molar ratios of CoFe2:CoFe2O4 and a great change in magnetic parameters were observed with the change in heating temperature from 300°C to 400°C, and the dominance of dipole interaction over exchange coupling in the interparticle interactions was confirmed by the steps in magnetic hysteresis loops and the negative Henkel plots. However, in the nanoceramics, significant enhancement in exchange coupling was found when the sintering temperature was raised to 500°C and 650°C, which was confirmed by both the positivity of Henkel plot and the single-phase style of the magnetic hysteresis loop.