Preparation and Research of Bi-YIG Nanoparticles via LTCC

摘要

Y3-xBixFe5O12 (Bi-YIG; x = 0.2-1.4) nanoparticles were successfully prepared at 925 degrees C by a solid state reaction method using low temperature co-firing ceramic technology. The properties of the materialwerecharacterized using x-ray powder diffraction, a scanning electron microscope and differential scanning calorimetry. The test results reveal that the crystallinity, size and sintering temperature are obviously related to Bi concentration. It is proved that the addition of Bi(2)0(3) can significantly decrease the sintering temperature, change microstructures and influence magnetic properties. The reason is that the sinteringaid (Bi(2)0(3)) forms a liquid phase in the sintering process, accelerating the diffusion of the yttrium iron garnet (YIG) particles, the transformation of phases, and the formation of new substances. In addition, the liquid phase can greatly facilitate the rearrangement and mass transfer of the YIG particles, so it can promote sintering and drastically decrease the sintering temperature. It is also confirmed that the turning point (x = 0.8) is the best Bi concentration. Moreover, the dynamic properties of ferromagnetic resonance (FMR) curves were studied in field sweep and frequency sweep modes, and the symmetry and asymmetry mechanisms of the FMR spectrum were researched. Finally, The Bastrukov theory, and the Landau-Lifshitz model and inhomogeneous broadening or Gilbert damping (LLG model) were used to analyse the resonance mechanism. By comparing the advantages and disadvantages of the two fitting mechanisms, it is found that the fitting of the LLG model is the best.