Microstructure and temperature dependence of magnetic properties of CuO-added MnZn ferrites

Abstract

MnZn ferrites with the chemical formula Mn 0.68 Zn 0.25 Fe 2.07 O 4 have been prepared by a conventional ceramic technique. Then, the effects of CuO addition on the microstructure and temperature dependence of magnetic properties of MnZn ferrites were investigated by characterizing the fracture surface micrograph and measuring the magnetic properties over a temperature ranging from 25 to 120°C. The results show that the lattice constant and average grain size increase with the increase of CuO concentration. When the CuO concentration is below 0.07 wt.%, the initial permeability and saturation magnetic flux density increase monotonously, and the temperature of the secondary maximum peak in the curve of initial permeability versus temperature and the lowest power loss shift to a lower temperature with the increase of CuO concentration. However, excessive CuO concentration (>0.07 wt.%) results in abnormal grain growth and porosity increase, which causes the initial permeability and saturation magnetic flux density decrease and the power loss increase at room temperature. Furthermore, the temperature of the secondary maximum peak in the curve of initial permeability versus temperature and the lowest power loss shift to a higher temperature.

Structure, Spectra, Morphology, and Magnetic Properties of Nb5+ Ion-Substituted Sr Hexaferrites

“…The properties of ferrite also depend on the microstructure. Ion substitution is a common method to adjust the properties based on alteration of the crystal structure, such as by La [4], Al [5], Mn [6], Cr [7], or Nd [8], or multiple ion substitution, such as of La-Zn [9], Co-Zr [10], Pr-Zn [11], Bi-La-Y [12], or Bi-Co-Ti [13]. Previous results have demonstrated that the properties of the composites can be improved and reduced in different degrees to meet the needs in various fields.…”