Solid State Reaction Mechanism And Electromagnetic Properties Of YIG/NiZn Ferrite Composite Substrate

In this paper,garnet ferrite obtained by ion doping with chemical formula Bi_0.5Y_1.5-xCa_1+xZr_xV_0.5Fe_4.5-xO₁₂（x=0.00,0.25,0.50,0.75,1.00）was used as the outer ring of the microwave circulator substrate.The morphology and electromagnetic properties of ferrite were tested by X-ray diffraction,scanning electron microscopy,Raman spectroscopy,transmission electron microscopy,vibrating sample magnetometer and vector network analyzer Optimal performance Bi_0.5Y_1.0Ca_1.5Zr_0.5V_0.5Fe_4.0O₁₂ samples were selected to bond with different chemical composition of the inner cores Ni_0.76Zn_0.1Cu_0.1Mn_0.04Co_xFe_1.98-xO_3.97（x=0.00,0.01,0.03,0.05,0.07）.The influence mechanism of solid state reaction on the phase structure and electromagnetic properties of co-fired composite substrate was investigated.（1）There is no new phase in the two ferrite materials before and after the composite,and the lattice spacing of garnet decreased gradually due to ions diffusion in the composite co-fired substrate.The addition of Co³⁺ions improves ion diffusion,and V⁵⁺ions with small radius in garnet are replaced by the ions with large radius in spinel.Some regions are distorted seriously for the enrichment of Bi³⁺ions.When the doping amount of Co³⁺ions is x=0.03,the red shift of the spinel occurs,indicating that the ions with a larger ion radius replaces the ions at the oxygen tetrahedral site（A site）of the spinel.The enrichment of Zr⁴⁺and Y³⁺ions existed in all composite substrates.The enrichment of Ca²⁺and V⁵⁺ions in composite substrates 1#,4#and 5#were accompanied by a generally low concentration of Zr⁴⁺and Y³⁺ions in the same regions.（2）The electrovalence conversion between Fe³⁺and Fe²⁺ions was inhibited after the composite spinel,so the dielectric constant and dielectric loss are lower than before the composite.The dielectric constant and dielectric loss of garnet do not change significantly before and after the composite.When the doping amount of Co³⁺ions achieved 0.03,the spinel oxygen tetrahedron（A site）after composite is replaced by diamagnetic ions,the saturation magnetization has been increased and the linewidth of ferromagnetic resonance has been decreased.Due to the diffusion of Zr⁴⁺ions,the saturation magnetization of garnet has been decreased and the linewidth of ferromagnetic resonance has been increased in return.The electromagnetic properties of composite substrate 3#are relatively stable.After composite,the dielectric constant of spinel changes from 11 to 10,the dielectric loss remains 8×10^-4 arround,and the saturation magnetization decreases from 39.744 emu/g to 36.157 emu/g.The linewidth of ferromagnetic resonance decreases from 306 Oe to 207 Oe.The dielectric constant and dielectric loss of garnet remain about 17 and 8×10^-4,respectively.The saturation magnetization decreases from 17.452 emu/g to 12.562 emu/g,and the linewidth of ferromagnetic resonance changes from 118 Oe to 142 Oe.The circulator composite substrate prepared by has tightly interface bond,low ion cross-diffusion concentration,and stable performance of inner core and outer ring ferrite,which can be used as the key material of microwave circulator in microwave communication system.