Dielectric behavior of Bi-Fe_3O_4 nanocomposite and Fe_3O_4 nanoparticles prepared via mechanochemical processing

摘要

Bi-Fe_3O_4 nanocomposite and Fe_3O_4 nanoparticles were prepared via mechanochemical processing. Structural, compositional, and morphological characterizations of products were carried out by using X-ray diffraction, Scanning electron microscopy and Transmission electron microscopy. The investigation of dielectric constant (ε'). dielectric loss tangent (tan δ), and AC resistivity was carried out in an applied field with frequency range of 100-1 MHz and at temperatures from 79 to 300 K. The variation of DC electrical resistivity with temperature was investigated with a two probe method from 79 to 300 K. It was found that ε'and tan δ decrease with increasing frequency and temperature. The DC resistivity decreases with increasing temperature. The experimental results show that both AC and DC resistivity, dielectric constants and activation energy of Bi-Fe_3O_4 nanocomposite are larger than those related to Fe_3O_4 and tan δ of the composite is much lower than that of Fe_3O_4.