The Ca-Sn co-substituted yttrium iron garnet(YIG)ferrite materials were prepared by the traditional oxide solid-state reaction method,and the influence of forming pressure on the density,morphology and magnetic proper...The Ca-Sn co-substituted yttrium iron garnet(YIG)ferrite materials were prepared by the traditional oxide solid-state reaction method,and the influence of forming pressure on the density,morphology and magnetic properties of YIG ferrite was systematically studied.The results show that the density of YIG ferrite green body increases with the increase of the forming pressure,while the density of its sintered body shows a trend of first increasing and then decreasing.At the same time,the ferromagnetic resonance(FMR)linewidth of YIG sample first decreases and then increases.Meanwhile,the effects of forming pressure on the saturation magnetization,remanence and coercivity of the sample can be ignored.This study proves that the density and FMR linewidth of YIG materials can be controlled by regulating the forming pressure and the best performance is obtained for the sample prepared under a forming pressure of 5 MPa.展开更多
Modern wireless communication and radar systems urgently require the application of low-loss and high-permittivity yttrium iron garnet(YIG)ferrite for highly efficient and integrated microwave circulators,isolators,fi...Modern wireless communication and radar systems urgently require the application of low-loss and high-permittivity yttrium iron garnet(YIG)ferrite for highly efficient and integrated microwave circulators,isolators,filters,etc.However,achieving a high dielectric constant,low dielectric loss,and narrow ferromagnetic resonance(FMR)linewidth simultaneously is challenging.Here,we synthesized Bi–Ca–Zr co-substituted YIG ferrites and comprehensively investigated the effects of multi-ion substitution on the polycrystalline microstructure and microwave electromagnetic properties of the material.The introduction of Bi3+ions at the crystallographic dodecahedral sites enhances the electronic polarization of single Fe^(3+)ions and the superexchange interaction between them.The substitution ofZr^(4+)ions for Fe^(3+)ions at octahedral sites suppresses the FMR linewidth broadening caused by magnetocrystalline anisotropy.Moreover,multi-ion substitution results in competition between liquid phase sintering and grain boundary pinning and influences the densification and grain growth processes,resulting in a non-uniform and dense microstructure composed of crystallites with a bimodal size distribution.This distinctive morphology further contributes to FMR linewidth reduction and permittivity increase.The optimized Bi–Ca–Zr co-substituted YIG ferrite has a narrow FMR linewidth of 33 Oe,high permittivity of 27,and high Curie temperature of 200℃,making it a promising candidate for next-generation microwave devices.展开更多
Compensated ferrimagnetic insulators are particularly interesting for enabling functional spintronic,optical,and microwave devices.Among many different garnets,Gd_(3)Fe_(5)O_(12)(GdIG)is a representative compensated f...Compensated ferrimagnetic insulators are particularly interesting for enabling functional spintronic,optical,and microwave devices.Among many different garnets,Gd_(3)Fe_(5)O_(12)(GdIG)is a representative compensated ferrimagnetic insulator.In this paper,we will study the evolution of the surface morphology,the magnetic properties,and the magnetization compensation through changing the following parameters:the annealing temperature,the growth temperature,the annealing duration,and the choice of different single crystalline garnet substrates.Our objective is to find the optimized growth condition of the GdIG films,for the purpose of achieving a strong perpendicular magnetic anisotropy(PMA)and a flat surface,together with a small effective damping parameter.Through our experiments,we have found that the surface roughness approaching 0.15 nm can be obtained by choosing the growth temperature around 700℃,together with an enhanced PMA.We have also found the modulation of magnetic anisotropy by choosing different single crystalline garnet substrates which change the tensile strain to the compressive strain.A measure of the effective magnetic damping parameter(α_(eff)=0.04±0.01)through a spin pumping experiment in a GdIG/Pt bilayer is also made.Through optimizing the growth dynamics of GdIG films,our results could be useful for synthesizing garnet films with a PMA,which could be beneficial for the future development of ferrimagnetic spintronics.展开更多
文摘The Ca-Sn co-substituted yttrium iron garnet(YIG)ferrite materials were prepared by the traditional oxide solid-state reaction method,and the influence of forming pressure on the density,morphology and magnetic properties of YIG ferrite was systematically studied.The results show that the density of YIG ferrite green body increases with the increase of the forming pressure,while the density of its sintered body shows a trend of first increasing and then decreasing.At the same time,the ferromagnetic resonance(FMR)linewidth of YIG sample first decreases and then increases.Meanwhile,the effects of forming pressure on the saturation magnetization,remanence and coercivity of the sample can be ignored.This study proves that the density and FMR linewidth of YIG materials can be controlled by regulating the forming pressure and the best performance is obtained for the sample prepared under a forming pressure of 5 MPa.
基金supported by the National Natural Science Foundation of China(Nos.52372255 and 52402332)the Science and Technology Department of Sichuan Province(Nos.2022JDTD0018,2024NSFSC0999,and 2024ZHCG0135)+1 种基金the Sichuan Province Engineering Research Center for Broadband Microwave Circuit High Density Integration(No.BMERC004-2023-07)the Science and Technology Department of Guizhou Province(No.QKHZC(2022)-055).
文摘Modern wireless communication and radar systems urgently require the application of low-loss and high-permittivity yttrium iron garnet(YIG)ferrite for highly efficient and integrated microwave circulators,isolators,filters,etc.However,achieving a high dielectric constant,low dielectric loss,and narrow ferromagnetic resonance(FMR)linewidth simultaneously is challenging.Here,we synthesized Bi–Ca–Zr co-substituted YIG ferrites and comprehensively investigated the effects of multi-ion substitution on the polycrystalline microstructure and microwave electromagnetic properties of the material.The introduction of Bi3+ions at the crystallographic dodecahedral sites enhances the electronic polarization of single Fe^(3+)ions and the superexchange interaction between them.The substitution ofZr^(4+)ions for Fe^(3+)ions at octahedral sites suppresses the FMR linewidth broadening caused by magnetocrystalline anisotropy.Moreover,multi-ion substitution results in competition between liquid phase sintering and grain boundary pinning and influences the densification and grain growth processes,resulting in a non-uniform and dense microstructure composed of crystallites with a bimodal size distribution.This distinctive morphology further contributes to FMR linewidth reduction and permittivity increase.The optimized Bi–Ca–Zr co-substituted YIG ferrite has a narrow FMR linewidth of 33 Oe,high permittivity of 27,and high Curie temperature of 200℃,making it a promising candidate for next-generation microwave devices.
基金Project supported by the National Key R&D Program of China(Grant Nos.2017YFA0206200 and 2016YFA0302300)the Basic Science Center Project of the National Natural Science Foundation of China(Grant No.51788104)+2 种基金the National Natural Science Foundation of China(Grant Nos.11774194,11804182,51831005,and 11811082)Beijing Natural Science Foundation(Grant No.Z190009)the Beijing Advanced Innovation Center for Future Chip(ICFC).
文摘Compensated ferrimagnetic insulators are particularly interesting for enabling functional spintronic,optical,and microwave devices.Among many different garnets,Gd_(3)Fe_(5)O_(12)(GdIG)is a representative compensated ferrimagnetic insulator.In this paper,we will study the evolution of the surface morphology,the magnetic properties,and the magnetization compensation through changing the following parameters:the annealing temperature,the growth temperature,the annealing duration,and the choice of different single crystalline garnet substrates.Our objective is to find the optimized growth condition of the GdIG films,for the purpose of achieving a strong perpendicular magnetic anisotropy(PMA)and a flat surface,together with a small effective damping parameter.Through our experiments,we have found that the surface roughness approaching 0.15 nm can be obtained by choosing the growth temperature around 700℃,together with an enhanced PMA.We have also found the modulation of magnetic anisotropy by choosing different single crystalline garnet substrates which change the tensile strain to the compressive strain.A measure of the effective magnetic damping parameter(α_(eff)=0.04±0.01)through a spin pumping experiment in a GdIG/Pt bilayer is also made.Through optimizing the growth dynamics of GdIG films,our results could be useful for synthesizing garnet films with a PMA,which could be beneficial for the future development of ferrimagnetic spintronics.
