Microwave Absorbing and Magnetic Properties of the Polyaniline-Co0.7Cr0.1Zn0.2Fe2O4 Composites

Abstract

The spinel cobalt chromium zinc ferrites (Co_0.7Cr_0.1Zn_0.2Fe₂O₄) and the polyaniline (PANI)-Co_0.7Cr_0.1Zn_0.2Fe₂O₄ composites were prepared by polyacrylamide gel and an in situ polymerization method, respectively. The structure of the synthesized material was characterized by X-ray diffraction (XRD) and Fourier transform infrared spectrometer (FT-IR), which shows that the spinel Co_0.7Cr_0.1Zn_0.2Fe₂O₄ ferrites and the PANI-Co_0.7Cr_0.1Zn_0.2Fe₂O₄ composites are obtained. Because a small amount Co²⁺ ion of the octahedron ferrite is replaced by Cr³⁺ ions, the lattice constant of the Co_0.8Zn_0.2Fe₂O₄ ferrites reduces from 0.8409nm to 0.8377nm. The magnetic properties of the two materials were investigated using vibrating sample magnetometer (VSM). The VSM results confirm that the saturation magnetization (Ms), remnant magnetization (Mr) and coercive force (Hc) of the PANI-Co_0.7Cr_0.1Zn_0.2Fe₂O₄ composites are 8.80emu/g, 3.14emu/g and 37.22kA/m, respectively, which are smaller than those of the Co_0.7Cr_0.1Zn_0.2Fe₂O₄ ferrites. The microwave absorbing capability of the two materials were studied by wave-guide method. In the measuring frequency range of 5.0~20.0GHz, two reflection loss maximum value of the PANI-Co_0.7Cr_0.1Zn_0.2Fe₂O₄ composites appear at 14.1GHz and 17.9GHz with -13.17dB and -15.36dB, respectively, which is obviously higher than those of the Co_0.7Cr_0.1Zn_0.2Fe₂O₄ ferrites.

DOI: http://dx.doi.org/10.5755/j01.ms.22.3.7177