Effect of Bi-substitution on the microstructure and electromagnetic properties of YCaZrVIG with low sintering temperature

Bi substituted YCaZrVIG ferrites, Y2.3−xBixCa0.7Zr0.3V0.2Fe4.42O12 (x=0.1, 0.25, 0.4, 0.5, 0.75) ferrites were prepared by conventional oxide method. The addition of Bi2O3 promoted the sintering performance and lowered the sintering temperature from 1420–1230 °C. However, it also resulted in the formation of minor second phases and the decrease of grain size. With the increase of Bi concentration, the dielectric constant increases linearly and then remains unchanged. The dielectric loss decreased firstly and then increased. The saturation magnetization (4πMs) almost retained unchanged as the Bi concentration increased except for the sample with 0.75. The coercivity (Hc) decreased firstly and reached the minimum of 1.32 Oe at 0.25, and then rose when x>0.25, which was related to the facility of magnetic domain wall motion and magnetic moment reverse. Moderate addition of Bi also can increase the remanence (Br) by improving sintering process. Additionally, we got the optimum electromagnetic properties in the samples with x=0.25 at 1230 °C: RD>97%, εr=15.7, tan δe=2.48×10−4, Hc=1.32Oe, 4πMS=1663 Gs, Br=583.91 Gs.