In this paper, the oriented M-type barium ferrite （BaM） thick films with different thicknesses are prepared by tape casting. It is found that the crystallographic alignment degree （f）, the pore and the squareness ...In this paper, the oriented M-type barium ferrite （BaM） thick films with different thicknesses are prepared by tape casting. It is found that the crystallographic alignment degree （f）, the pore and the squareness ratio （Mr/Ms） are not affected by the thickness of the film. XRD and SEM results show that the thick film has hexagonal morphology with a crystal texture of c-axis grains perpendicular to film plane. The hysteresis curve indicates that the BaM thick film exhibits a self-biased property with a remanent magnetization of 3.30 T, a squareness ratio （Mr/Ms） of 0.81, and a coercivity of 0.40 T. The results show that the BaM thick film has potential for use in self-biasing microwave devices, and also proves that the tape casting technique is capable of fabricating high-quality barium ferrite films, thus providing a unique opportunity to realize the large area production of thick film.展开更多
Barium ferrite（Ba M） thin films are deposited on platinum coated silicon wafers by pulsed laser deposition（PLD）.The effects of deposition substrate temperature on the microstructure,magnetic and microwave properti...Barium ferrite（Ba M） thin films are deposited on platinum coated silicon wafers by pulsed laser deposition（PLD）.The effects of deposition substrate temperature on the microstructure,magnetic and microwave properties of Ba M thin films are investigated in detail.It is found that microstructure,magnetic and microwave properties of Ba M thin film are very sensitive to deposition substrate temperature,and excellent Ba M thin film is obtained when deposition temperature is 910℃ and oxygen pressure is 300 m Torr（1 Torr = 1.3332×102Pa）.X-ray diffraction patterns and atomic force microscopy images show that the best thin film has perpendicular orientation and hexagonal morphology,and the crystallographic alignment degree can be calculated to be 0.94.Hysteresis loops reveal that the squareness ratio（Mr/Ms） is as high as 0.93,the saturated magnetization is 4004 Gs（1 Gs = 104T）,and the anisotropy field is 16.5 kOe（1 Oe = 79.5775 A·m-1）.Ferromagnetic resonance measurements reveal that the gyromagnetic ratio is 2.8 GHz/kOe,and the ferromagnetic resonance linewith is108 Oe at 50 GHz,which means that this thin film has low microwave loss.These properties make the Ba M thin films have potential applications in microwave devices.展开更多
The polyaniline-barium ferrite composite was synthesized by in situ polymerization of aniline in the presence of BaFe12019 nanoparticles. The structure, morphology, and magnetic properties of samples were characterize...The polyaniline-barium ferrite composite was synthesized by in situ polymerization of aniline in the presence of BaFe12019 nanoparticles. The structure, morphology, and magnetic properties of samples were characterized by powder X-ray diffraction （XRD）, Fourier transform infrared （FTIR）, scanning electron microscopy （SEM） and vibrating sample magnetometer （VSM）. The testing results showed that the composite exhibited the ferromagnetic and electric behaviors, which benefit for the application of electromagnetic interfence.展开更多
A series of doped barium hexaferrites BaFe12-2xMnxSnxO19 （x = 0.0-1.0） particles were prepared by the co-precipitation/molten salt method. The particle size and crystalline of the samples BaFe12-2xMnxSnxO19 decrease...A series of doped barium hexaferrites BaFe12-2xMnxSnxO19 （x = 0.0-1.0） particles were prepared by the co-precipitation/molten salt method. The particle size and crystalline of the samples BaFe12-2xMnxSnxO19 decrease with an increase in the doping amount x. When x is less than 0.8, the pure BaFe12-2xMnxSnxO19 particles with hexagonal plate morphology are obtained. The effects of substitution on magnetic properties were evaluated and compared to nomal BaFe12O19. The specific magnetizations （Ms） of doped materials have been significantly improved. Among all these compositions, the BaFe10.4Mn0.8Sn0.8O19 sample has the highest Ms value of 81.8 A？m2？kg-1 at room temperature and its intrinsic coercivity （Hc） is 44.5 kA？m-1. The as-prepared doped barium ferrites exhibit a low temperature coefficient of coercivity close to zero. The coercivity is independent of temperature when x is in the a range 0.5-0.7.展开更多
基金Project supported by the Foundation of the Ministry of Science and Technology of China (Grant No. 2009GJE00033)the National Natural Youth Fund of China (Grant No. 61001025)the National Program for Science and Technology Development of Guangdong Province,China (Grant No. 2010B090400314)
文摘In this paper, the oriented M-type barium ferrite （BaM） thick films with different thicknesses are prepared by tape casting. It is found that the crystallographic alignment degree （f）, the pore and the squareness ratio （Mr/Ms） are not affected by the thickness of the film. XRD and SEM results show that the thick film has hexagonal morphology with a crystal texture of c-axis grains perpendicular to film plane. The hysteresis curve indicates that the BaM thick film exhibits a self-biased property with a remanent magnetization of 3.30 T, a squareness ratio （Mr/Ms） of 0.81, and a coercivity of 0.40 T. The results show that the BaM thick film has potential for use in self-biasing microwave devices, and also proves that the tape casting technique is capable of fabricating high-quality barium ferrite films, thus providing a unique opportunity to realize the large area production of thick film.
基金Project supported by the Open Foundation of State Key Laboratory of Electronic Thin Films and Integrated Devices(Grant No.KFJJ201506)the Scientific Research Starting Foundation of Hainan University(Grant No.kyqd1539)the Natural Science Foundation of Hainan Province(Grant No.20165187)
文摘Barium ferrite（Ba M） thin films are deposited on platinum coated silicon wafers by pulsed laser deposition（PLD）.The effects of deposition substrate temperature on the microstructure,magnetic and microwave properties of Ba M thin films are investigated in detail.It is found that microstructure,magnetic and microwave properties of Ba M thin film are very sensitive to deposition substrate temperature,and excellent Ba M thin film is obtained when deposition temperature is 910℃ and oxygen pressure is 300 m Torr（1 Torr = 1.3332×102Pa）.X-ray diffraction patterns and atomic force microscopy images show that the best thin film has perpendicular orientation and hexagonal morphology,and the crystallographic alignment degree can be calculated to be 0.94.Hysteresis loops reveal that the squareness ratio（Mr/Ms） is as high as 0.93,the saturated magnetization is 4004 Gs（1 Gs = 104T）,and the anisotropy field is 16.5 kOe（1 Oe = 79.5775 A·m-1）.Ferromagnetic resonance measurements reveal that the gyromagnetic ratio is 2.8 GHz/kOe,and the ferromagnetic resonance linewith is108 Oe at 50 GHz,which means that this thin film has low microwave loss.These properties make the Ba M thin films have potential applications in microwave devices.
基金This work was supported by the National Nature Science Foundation of China under Grant No.60425102.
文摘The polyaniline-barium ferrite composite was synthesized by in situ polymerization of aniline in the presence of BaFe12019 nanoparticles. The structure, morphology, and magnetic properties of samples were characterized by powder X-ray diffraction （XRD）, Fourier transform infrared （FTIR）, scanning electron microscopy （SEM） and vibrating sample magnetometer （VSM）. The testing results showed that the composite exhibited the ferromagnetic and electric behaviors, which benefit for the application of electromagnetic interfence.
基金Funded by National Natural Science Foundation of China (Nos.20801016, 20701013, and 60971020)Postdoctoral Foundation of Heilongjiang Province(No. LRB07-231)Fundamental Research Funds for the Central Universities(No.HEUCF201210010)
文摘A series of doped barium hexaferrites BaFe12-2xMnxSnxO19 （x = 0.0-1.0） particles were prepared by the co-precipitation/molten salt method. The particle size and crystalline of the samples BaFe12-2xMnxSnxO19 decrease with an increase in the doping amount x. When x is less than 0.8, the pure BaFe12-2xMnxSnxO19 particles with hexagonal plate morphology are obtained. The effects of substitution on magnetic properties were evaluated and compared to nomal BaFe12O19. The specific magnetizations （Ms） of doped materials have been significantly improved. Among all these compositions, the BaFe10.4Mn0.8Sn0.8O19 sample has the highest Ms value of 81.8 A？m2？kg-1 at room temperature and its intrinsic coercivity （Hc） is 44.5 kA？m-1. The as-prepared doped barium ferrites exhibit a low temperature coefficient of coercivity close to zero. The coercivity is independent of temperature when x is in the a range 0.5-0.7.
基金supported by the National Natural Science Foundation of China(Grant Numbers 51702285,51772269)the Zhejiang Provincial Natural Science Foundation(Grant Number LY17F040003).
