Ni-Zn ferrite octahedral nanoparticles with high microwave permeability and high magnetic loss tangent

Ni-Zn ferrite octahedral nanoparticles with grain size of about 40 nm were synthesized via a low temperature hydrothermal route. The saturation magnetization (M-s) and coercive force (He) of the sample are 57.5 emu/g and 197 Oe, respectively. In 50 MHz-8 GHz frequency range, the complex permeability and complex permittivity for Ni-Zn ferrite/wax composites containing 60 wt% ferrite powders were measured by a vector network analyzer. The real part mu(r)' of the permeability exhibits high values between 4 and 1.65 in 50 MHz-2 GHz range, and the imaginary part mu(r)'' of the permeability presents a broad peak with a maximum value of 1.53 at 2.1 GHz, the calculated reflection loss of ferrite/wax coating with the thickness of 8 mm reaches -13 dB at 2.1 GHz. The results indicate the as-prepared Ni-Zn ferrite octahedral nanoparticles can have applications in biomedicine, and microwave absorption and electric devices. (C) 2013 Elsevier B.V. All rights reserved.