High dielectric constant(ε′)yttrium iron garnet ferrites were prepared by traditional oxide sintering process.The effects of Nb5+ substitution on the microstructure,crystal phase,density(d),porosity(p),lattice constant(a),saturation magnetization(4πMs),ferromagnetic resonance linewidth(ΔH)and dielectric constant of the materials sintered at different temperatures were investigated.The results show that Nb5+ substitution slightly increases the grain size of the material.Nb5+ substitution has no obvious effect on the crystal phase of the material,which is pure garnet phase.When sintered at 1020℃,with the increase of Nb5+ substitution amount x from 0 to 0.075,4πMs decreases from 1882 G to 1741 G,ΔH increases from 149.3 Oe to 180.2 Oe,the density decreases from 5.83 g/cm3 to 5.72 g/cm3,the average grain size(D)increases from 2.29 μm to 2.38 μm,the porosity increases from 1.7％to 3.0％,and ε′ has no obvious change.
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