The Preparation And Research Of High Performance YIG Ceramics And Films

Microwave ferrite devices play a more and more important role as the core parts of communication system.Yttrium iron garnet ferrite(Y₃Fe₅O₁₂,YIG)is a kind of excellent magnetic properties of ferrite materials.It's widely applied in microwave devices because of its good spin magnetic effect and low iron magnetic resonance linewidth.At present,miniaturization,fragmentation and integration are the direction of the development of magnetic devices.The application of materials to various devices in the form of films is an inevitable trend.Therefore,how to produce high-quality YIG films that meet the requirements of microwave devices is worth of further research.The target material is the foundation of the films and is one of the important factors to determine the films performance.Firstly,YIG bulks were prepared by sol-gel combined two-step sintering.Effect of the sintering temperature T₁,T₂ and holding time t were investigated.The average crystal size,relative density and internal microstructure of YIG bulks were investigated.Further tests were conducted to investigate the effect of these on the magnetic properties of the ferromagnetic resonance line.Finally,the preparation conditions of T₁=1300?,T₂=1225?and holding time t=18h had high quality YIG bulks with the average grain size was0.975?m,relative density 98.4%,and the saturation magnetization intensity reached27.18emu/g.Secondly,the YIG bulk was used as the target to prepare the film by PLD technique.The influence of different grain size YIG bulks deposition on the films performance was investigated.1?m,2.3?m,5?m and 10?m were used to deposit YIG film on Si and GGG substrate.The grain size of the target get smaller,the performance of films get better.The roughness of the film prepared by 1?m is 9nm on the Si substrate and 2nm on the GGG substrate;the crystallinity of the Si substrate is excellent,the full width at half maximum is only 0.101 degrees.The saturation magnetization?M_S?of this samples reached 189emu/cm³ on Si and 197.2emu/cm³ on GGG.Eventually,the films were prepared by double target deposition method.YIG target and Fe₂O₃ target or Y₂O₃ target according to the proportion of time 1:0,10:1,5:1 and 2:1 deposition film was prepared.The influence of the surface composition of the target material on the film performance was investigated.The best YIG films can be obtained by using YIG target and Y₂O₃ target deposition,and the deposition time ratio is 10:1.The surface morphology of the film is smooth,the element composition is basically consistent with YIG,and XRD has no obvious hybrid peaks,good crystallinity,and the saturation magnetization intensity reached 156.41emu/cm³.