Effects of Al3+ Substitution on Structural and Magnetic Behavior of CoFe₂O₄ Ferrite Nanomaterials

Qing Lin; Yun He; Jianmei Xu; Jinpei Lin; Zeping Guo; Fang Yang

doi:10.3390/nano8100750

Effects of Al³⁺ Substitution on Structural and Magnetic Behavior of CoFe₂O₄ Ferrite Nanomaterials

Nanomaterials (Basel). 2018 Sep 21;8(10):750. doi: 10.3390/nano8100750.

Authors

Qing Lin^{1

2}, Yun He^{3

4}, Jianmei Xu⁵, Jinpei Lin^{6

7}, Zeping Guo⁸, Fang Yang⁹

Affiliations

¹ College of Medical Informatics, Hainan Medical University, Haikou 571199, China. mossbauer2019@gxnu.edu.cn.
² Guangxi Key Laboratory of Nuclear Physics and Nuclear Technology, Guangxi Normal University, Guilin 541004, China. mossbauer2019@gxnu.edu.cn.
³ Guangxi Key Laboratory of Nuclear Physics and Nuclear Technology, Guangxi Normal University, Guilin 541004, China. hy@mailbox.gxnu.edu.cn.
⁴ Sate Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, Guangxi Normal University, Guilin 541004, China. hy@mailbox.gxnu.edu.cn.
⁵ College of Medical Informatics, Hainan Medical University, Haikou 571199, China. huyang@gxnu.edu.cn.
⁶ College of Medical Informatics, Hainan Medical University, Haikou 571199, China. hy@gxnu.edu.cn.
⁷ Guangxi Key Laboratory of Nuclear Physics and Nuclear Technology, Guangxi Normal University, Guilin 541004, China. hy@gxnu.edu.cn.
⁸ College of Physics and Technology, Guangxi Normal University, Guilin 541004, China. zepingguo@mailbox.gxnu.edu.cn.
⁹ College of Medical Informatics, Hainan Medical University, Haikou 571199, China. zepingguo@gxnu.edu.cn.

Abstract

A sol-gel autocombustion method was used to synthesize Al³⁺ ion-substituted cobalt ferrite CoAl_xFe_2-xO₄ (x = 0⁻1.5). According to X-ray diffraction analysis (XRD), cobalt ferrite was in a single cubic phase after being calcined at 1000 °C for 3 h. Moreover, the lattice constant decreased with increase in aluminum substituents. When the sample was analyzed by Scanning Electron Microscopy (SEM), we found that uniformly sized, well-crystallized grains were distributed in the sample. Furthermore, we confirmed that Al³⁺ ion-substituted cobalt ferrite underwent a transition from ferrimagnetic to superparamagnetic behavior; the superparamagnetic behavior was completely correlated with the increase in Al³⁺ ion concentration at room temperature. All these findings were observed in Mössbauer spectra. For the cobalt ferrite CoAl_xFe_2-xO₄, the coercivity and saturation magnetization decrease with an increase in aluminum content. When the annealing temperature of CoAl_0.1Fe_1.9O₄ was steadily increased, the coercivity and saturation magnetization initially increased and then decreased.

Keywords: Al substitution; Co-Al-Ferrite; Mössbauer; magnetic properties; sol-gel.

Grants and funding

11364004,11164002/National Natural Science Foundation of China