Effect of B_2O_3-Bi_2O_3-SiO_2-ZnO glass on the dielectric and magnetic properties of ferroelectric/ferromagnetic composite for low temperature cofired ceramic technology

摘要

Ni-Cu-Zn ferrite/BaTiO_3 composites with different additive amounts of B_2O_3-Bi_2O_3-SiO_2-ZnO (BBSZ) glass have been prepared by a conventional solid-reaction method and sintered at 900℃ to adapt to low temperature cofired ceramic (LTCC) technology. The dielectric and magnetic properties of the composites can be effectively improved with increasing BBSZ content. Here, the BBSZ glass mainly plays two roles, one is as a sintering aid promoting grain growth and the other is as a low permittivity phase or nonmagnetic phase leading to dilution effect on the dielectric or magnetic properties of the composites. The effect degree of above two roles is related to the variation in BBSZ content and has been discussed combining with the effective medium theory. The lower and upper bounds for the effective permittivity and permeability have been given by the Maxwell-Garnett rules.