We are examining the behavior of a composite made of ferroelectrics with strong dielectric properties and ferrites with magnetic properties due to the rising need for materials for multipurpose devices.Many applicatio...We are examining the behavior of a composite made of ferroelectrics with strong dielectric properties and ferrites with magnetic properties due to the rising need for materials for multipurpose devices.Many application avenues will be favored by the pairing of these materials’individual qualities with one another.Perovskite and U-type hexaferrite composite materials have been chosen for this study based on their magnetic and dielectric properties.The composites,(1−x)PLT−x(Ba1−3xNd2x)4Co2Fe36O60 where x=0.52,0.54,0.56,0.58 are prepared by solid state reaction method and phase formation was examined.Consideration has been given to the magnetic,dielectric,and magneto-dielectric properties.This work has established the link between the electric and magnetic domains while applying electric and magnetic forces to the materials.The magneto-dielectric research revealed magneto-electric coupling in all of the samples.However,the sample shows the maximum coupling for x=0.54 with MDR%values of 93.17%,which might be because this sample appears to have a high magneto-resistance(161%).展开更多
Magneto-dielectric properties of Co_(2)Z ferrite materials are tuned via Gd doping for applications in high-frequency antennas and filters in the present work.Ba_(3)Co_(2)Fe_(24-x)Gd_(x)O_(41)(x=0.00,0.05,0.10,0.15,an...Magneto-dielectric properties of Co_(2)Z ferrite materials are tuned via Gd doping for applications in high-frequency antennas and filters in the present work.Ba_(3)Co_(2)Fe_(24-x)Gd_(x)O_(41)(x=0.00,0.05,0.10,0.15,and 0.20)materials are successfully prepared by using solid-state method at 925℃for 4 h with 2.5-wt%Bi_(2)O_(3)sintering aids.The content of Gd^(3+)ion can affect micromorphology,grain size,bulk density,and magneto-dielectric properties of the ferrite.With Gd^(3+)ion content increasing,saturation magnetization(Ms)first increases and then decreases.The maximum value of Ms is 44.86 emu/g at x=0.15.Additionally,sites occupied by Gd^(3+)ions can change magnetic anisotropy constant of the ferrite.Magnetocrystalline anisotropy constant(K_1)is derived from initial magnetization curve,and found to be related to spin-orbit coupling and intersublattice interactions between metal ions.The real part of magnetic permeability(μ′)and real part of dielectric permittivity(ε′)are measured in a frequency range of 10 MHz-1 GHz.When x=0.15,material has excellent magneto-dielectric properties(μ′≈12.2 andε′≈17.61),low magnetic loss(tanδμ≈0.03 at 500 MHz),and dielectric loss(tanδε≈0.04 at 500 MHz).The results show that Gd-doped Co_(2)Z ferrite has broad application prospects in multilayer filters and high-frequency antennas.展开更多
A study of the dielectric, magnetic and structural properties of composites based on M-type barium hexaferrite BFO (BaFe12O19) and SBN (SrBi2Nb2O9) is presented. The magneto-dielectric matrix composite (SrBi2Nb2O9)x(B...A study of the dielectric, magnetic and structural properties of composites based on M-type barium hexaferrite BFO (BaFe12O19) and SBN (SrBi2Nb2O9) is presented. The magneto-dielectric matrix composite (SrBi2Nb2O9)x(BaFe12O19)100–x, (x = 0,25,50,75 and 100 wt%) were prepared by using a new procedure based in the solid state method. X-Ray powder diffraction patterns, Raman and Infrared spectroscopy, M?ssbauer spectroscopy and scanning electron microscopy (SEM) were carried out for better understanding of the microstructural, dielectric and magnetic properties. Radiofrequency (RF) dielectric permittivity, dielectric loss measurements and magnetic and electric hysteresis loops properties are also discussed throughout this paper. The hysteresis loops showed that composite samples preserve the ferrimagnetism and ferroelectricity for hexaferrite when SBN is added to the composite (BFO25P), although they become less coercive. In addition, the effects of organic binders group (TEOS, PVA and glycerin) on structural properties were also investigated.展开更多
This work promotes the room temperature energy storage properties of the multiferroics.In this approach,impacts of PrFeO_(3)doping on PT-based solid solutions(Pb1−xPrxTi1−xFexO_(3),x=0.21,0.22,0.23,0.24,0.25 and 0.26)...This work promotes the room temperature energy storage properties of the multiferroics.In this approach,impacts of PrFeO_(3)doping on PT-based solid solutions(Pb1−xPrxTi1−xFexO_(3),x=0.21,0.22,0.23,0.24,0.25 and 0.26)have been explored.X-ray diffraction(XRD)patterns were used to estimate the crystallographic parameters,confirming the single phase tetragonal structure.The ferroelectric Curie temperature(Tc FE)is observed to drop from 410 K to below room temperature as the Pr concentration increases.The ferroelectric P-E loops were used to determine the energy storage values at room temperature.The sample x=0.24 achieved the maximum value of energy storage density of 362.25 mJ/cm^(3)with the efficiency of 40.5%.The ferroelectric P-E loops were used to determine the energy storage values at room temperature.The validity of magnetoelectric coupling in all samples was confirmed by magneto-dielectric studies and found that the sample x=0.24 shows the maximum response with the coupling coefficient(γ)=15.54 g^(2)/emu^(2).展开更多
The U-type hexaferrites(Ba_(1−3x)La_(2x))4Co_(2)Fe_(36)O_(60)(x=0,0.05,0.10,0.15,0.20,0.25)have been synthesized by auto-combustion method.The work involves the study of structural,microstructural,dielectric,magnetic ...The U-type hexaferrites(Ba_(1−3x)La_(2x))4Co_(2)Fe_(36)O_(60)(x=0,0.05,0.10,0.15,0.20,0.25)have been synthesized by auto-combustion method.The work involves the study of structural,microstructural,dielectric,magnetic and magneto-dielectric properties of the prepared materials.The structural analysis has been done by X-ray diffraction technique along with Le Bail refinement which confirmed the pure hexagonal phase for all the samples.The microstructural analysis has been carried out by field-emission scanning electron microscopy.The vibrating sample magnetometer is used to measure the magnetic properties.The sample with a composition of x=0.15 has shown the maximum magnetization of approximately 73.31 emu/g with the remnant magnetization of 38.89 emu/g and coercive field of 1.77 kOe at room temperature.Moreover,the same sample has delivered the maximum mag-netodielectric response of about 54.18%at 1.5-T field.展开更多
Ferrite ceramics,Ni_(0.88)Zn_(0.07)Co_(0.05)Fe_(1.98)O_(4),with the addition of 4 wt.%Bi_(2)O_(3) as sintering aid,were fabricated by using a simple one-step processing without involving the step of calcination.X-ray ...Ferrite ceramics,Ni_(0.88)Zn_(0.07)Co_(0.05)Fe_(1.98)O_(4),with the addition of 4 wt.%Bi_(2)O_(3) as sintering aid,were fabricated by using a simple one-step processing without involving the step of calcination.X-ray diffraction(XRD)results indicated that single phase ferrite ceramics can be achieved after sintering at 1000℃ for 2 h.The samples demonstrated relative densities in the range of 97-99%.Desired magneto-dielectric properties have been approached by adjusting the sintering temperature and sintering time duration.This technique is believed to be applicable to other ceramic materials.展开更多
Magnetic,dielectric and DC conductive properties of Ni_(0.95-x)Zn_(x)Co_(0.05)Fe_(1.90)Mn_(0.02)O_(4)(with x=0-0.20 at an interval of 0.05)ferrite ceramics were studied,in order to develop magneto-dielectric materials...Magnetic,dielectric and DC conductive properties of Ni_(0.95-x)Zn_(x)Co_(0.05)Fe_(1.90)Mn_(0.02)O_(4)(with x=0-0.20 at an interval of 0.05)ferrite ceramics were studied,in order to develop magneto-dielectric materials with almost equal values of relative permeability and permittivity,for the miniaturization of HF(3-30 MHz)and VHF(30-90MHz and 100-300 MHz)antennas.The ferrite ceramics were prepared by using the conventional two-step sintering process.The real part of relative permeability is increased almost linearly with increasing concentration of Zn,while that of relative permittivity keeps nearly unchanged.It is found that promising magneto-dielectric materials,with close values of real permeability and permittivity over 30-90 MHz(VHF),can be obtained for the samples at Zn concentrations between x=0.05 and x=0.10.展开更多
Silver nanoparticles of diameters 3.4 to 13.2 nm grown at the interfaces between silicate glass and some oxide crystallites exhibited about six orders of magnitude reduction in resistivity for a relative humidity chan...Silver nanoparticles of diameters 3.4 to 13.2 nm grown at the interfaces between silicate glass and some oxide crystallites exhibited about six orders of magnitude reduction in resistivity for a relative humidity change from 25% to 80%. Sn-SnO2 nano core-shell structure prepared within a gel-derived silica glass film by electrodeposition technique followed by heat treatment showed large change in resistivity as a function of humidity. The resistivity also changed due to gas flow of CO2, C2H5OH and NO2, respectively. The latter arose because of reduction/oxidation of Sn4+/Sn2+ species present at the shell layer of the nanostructures. Nickel nanosheets of thickness ~0.6 nm grown within the interlayer spaces of Na-4 mica crystallites showed a change of dielectric permittivity (5%) for an applied magnetic field of 1.2 Tesla. An inhomogeneous model was used to explain this behavior. Two dimensional CuO phase was grown within the channels of diameter ~5 nm of mesoporous SiO2 structure. A magnetodielectric (MD) parameter M.D. of 4.4% was obtained in this case. BaTiO3 nanoparticles of diameter ~25 nm having pores with diameter 10 nm showed multiferroic behavior which arose due to the presence of oxygen vacancies as a result of large surface area present. An M.D. parameter of 11% was found. Similarly mesoporous LiNbO3 of 10 nm diameter showed an M.D. parameter of ~4.5% at a magnetic field 1 Tesla. A giant magnetocapacitance effect with a value of 44% at 1.5 T was observed in nickel zinc ferrite (NZF) impregnated mesoporous silica. A magnetocapacitance of 51% at magnetic field 1.7 T was found in the case of nanocomposites comprising of iron ion containing silica based nanoglass and mesoporous silica. In the last two examples the behavior was explained on the basis of Catalan model of space-charge polarization with extracted values of magnetoresistance of the NZF and nanoglass phases being 58%.展开更多
文摘We are examining the behavior of a composite made of ferroelectrics with strong dielectric properties and ferrites with magnetic properties due to the rising need for materials for multipurpose devices.Many application avenues will be favored by the pairing of these materials’individual qualities with one another.Perovskite and U-type hexaferrite composite materials have been chosen for this study based on their magnetic and dielectric properties.The composites,(1−x)PLT−x(Ba1−3xNd2x)4Co2Fe36O60 where x=0.52,0.54,0.56,0.58 are prepared by solid state reaction method and phase formation was examined.Consideration has been given to the magnetic,dielectric,and magneto-dielectric properties.This work has established the link between the electric and magnetic domains while applying electric and magnetic forces to the materials.The magneto-dielectric research revealed magneto-electric coupling in all of the samples.However,the sample shows the maximum coupling for x=0.54 with MDR%values of 93.17%,which might be because this sample appears to have a high magneto-resistance(161%).
基金the National Key Research and Development Program of China(Grant No.2022YFB3504800)the National Natural Science Foundation of China(Grant Nos.61901142,52003256,and 51902037)the Natural Science Foundation of Shanxi Province,China(Grant No.201901D211259)。
文摘Magneto-dielectric properties of Co_(2)Z ferrite materials are tuned via Gd doping for applications in high-frequency antennas and filters in the present work.Ba_(3)Co_(2)Fe_(24-x)Gd_(x)O_(41)(x=0.00,0.05,0.10,0.15,and 0.20)materials are successfully prepared by using solid-state method at 925℃for 4 h with 2.5-wt%Bi_(2)O_(3)sintering aids.The content of Gd^(3+)ion can affect micromorphology,grain size,bulk density,and magneto-dielectric properties of the ferrite.With Gd^(3+)ion content increasing,saturation magnetization(Ms)first increases and then decreases.The maximum value of Ms is 44.86 emu/g at x=0.15.Additionally,sites occupied by Gd^(3+)ions can change magnetic anisotropy constant of the ferrite.Magnetocrystalline anisotropy constant(K_1)is derived from initial magnetization curve,and found to be related to spin-orbit coupling and intersublattice interactions between metal ions.The real part of magnetic permeability(μ′)and real part of dielectric permittivity(ε′)are measured in a frequency range of 10 MHz-1 GHz.When x=0.15,material has excellent magneto-dielectric properties(μ′≈12.2 andε′≈17.61),low magnetic loss(tanδμ≈0.03 at 500 MHz),and dielectric loss(tanδε≈0.04 at 500 MHz).The results show that Gd-doped Co_(2)Z ferrite has broad application prospects in multilayer filters and high-frequency antennas.
文摘A study of the dielectric, magnetic and structural properties of composites based on M-type barium hexaferrite BFO (BaFe12O19) and SBN (SrBi2Nb2O9) is presented. The magneto-dielectric matrix composite (SrBi2Nb2O9)x(BaFe12O19)100–x, (x = 0,25,50,75 and 100 wt%) were prepared by using a new procedure based in the solid state method. X-Ray powder diffraction patterns, Raman and Infrared spectroscopy, M?ssbauer spectroscopy and scanning electron microscopy (SEM) were carried out for better understanding of the microstructural, dielectric and magnetic properties. Radiofrequency (RF) dielectric permittivity, dielectric loss measurements and magnetic and electric hysteresis loops properties are also discussed throughout this paper. The hysteresis loops showed that composite samples preserve the ferrimagnetism and ferroelectricity for hexaferrite when SBN is added to the composite (BFO25P), although they become less coercive. In addition, the effects of organic binders group (TEOS, PVA and glycerin) on structural properties were also investigated.
文摘This work promotes the room temperature energy storage properties of the multiferroics.In this approach,impacts of PrFeO_(3)doping on PT-based solid solutions(Pb1−xPrxTi1−xFexO_(3),x=0.21,0.22,0.23,0.24,0.25 and 0.26)have been explored.X-ray diffraction(XRD)patterns were used to estimate the crystallographic parameters,confirming the single phase tetragonal structure.The ferroelectric Curie temperature(Tc FE)is observed to drop from 410 K to below room temperature as the Pr concentration increases.The ferroelectric P-E loops were used to determine the energy storage values at room temperature.The sample x=0.24 achieved the maximum value of energy storage density of 362.25 mJ/cm^(3)with the efficiency of 40.5%.The ferroelectric P-E loops were used to determine the energy storage values at room temperature.The validity of magnetoelectric coupling in all samples was confirmed by magneto-dielectric studies and found that the sample x=0.24 shows the maximum response with the coupling coefficient(γ)=15.54 g^(2)/emu^(2).
文摘The U-type hexaferrites(Ba_(1−3x)La_(2x))4Co_(2)Fe_(36)O_(60)(x=0,0.05,0.10,0.15,0.20,0.25)have been synthesized by auto-combustion method.The work involves the study of structural,microstructural,dielectric,magnetic and magneto-dielectric properties of the prepared materials.The structural analysis has been done by X-ray diffraction technique along with Le Bail refinement which confirmed the pure hexagonal phase for all the samples.The microstructural analysis has been carried out by field-emission scanning electron microscopy.The vibrating sample magnetometer is used to measure the magnetic properties.The sample with a composition of x=0.15 has shown the maximum magnetization of approximately 73.31 emu/g with the remnant magnetization of 38.89 emu/g and coercive field of 1.77 kOe at room temperature.Moreover,the same sample has delivered the maximum mag-netodielectric response of about 54.18%at 1.5-T field.
基金supported by the Natural Science Fund of China(51762023)the JiangXi Association for Science and Technology,the Jiangxi Provincial Department of Education,and the Training Program of Outstanding Young Scientists in Jiangxi Province(20171BCB23070).
文摘Ferrite ceramics,Ni_(0.88)Zn_(0.07)Co_(0.05)Fe_(1.98)O_(4),with the addition of 4 wt.%Bi_(2)O_(3) as sintering aid,were fabricated by using a simple one-step processing without involving the step of calcination.X-ray diffraction(XRD)results indicated that single phase ferrite ceramics can be achieved after sintering at 1000℃ for 2 h.The samples demonstrated relative densities in the range of 97-99%.Desired magneto-dielectric properties have been approached by adjusting the sintering temperature and sintering time duration.This technique is believed to be applicable to other ceramic materials.
基金supported by the Natural Science Fund of China(51762023)the JiangXi Association for Science and Technology,the Jiangxi Provincial Department of Education,and the Training Program of Outstanding Young Scientists in Jiangxi Province(20171BCB23070).
文摘Magnetic,dielectric and DC conductive properties of Ni_(0.95-x)Zn_(x)Co_(0.05)Fe_(1.90)Mn_(0.02)O_(4)(with x=0-0.20 at an interval of 0.05)ferrite ceramics were studied,in order to develop magneto-dielectric materials with almost equal values of relative permeability and permittivity,for the miniaturization of HF(3-30 MHz)and VHF(30-90MHz and 100-300 MHz)antennas.The ferrite ceramics were prepared by using the conventional two-step sintering process.The real part of relative permeability is increased almost linearly with increasing concentration of Zn,while that of relative permittivity keeps nearly unchanged.It is found that promising magneto-dielectric materials,with close values of real permeability and permittivity over 30-90 MHz(VHF),can be obtained for the samples at Zn concentrations between x=0.05 and x=0.10.
文摘Silver nanoparticles of diameters 3.4 to 13.2 nm grown at the interfaces between silicate glass and some oxide crystallites exhibited about six orders of magnitude reduction in resistivity for a relative humidity change from 25% to 80%. Sn-SnO2 nano core-shell structure prepared within a gel-derived silica glass film by electrodeposition technique followed by heat treatment showed large change in resistivity as a function of humidity. The resistivity also changed due to gas flow of CO2, C2H5OH and NO2, respectively. The latter arose because of reduction/oxidation of Sn4+/Sn2+ species present at the shell layer of the nanostructures. Nickel nanosheets of thickness ~0.6 nm grown within the interlayer spaces of Na-4 mica crystallites showed a change of dielectric permittivity (5%) for an applied magnetic field of 1.2 Tesla. An inhomogeneous model was used to explain this behavior. Two dimensional CuO phase was grown within the channels of diameter ~5 nm of mesoporous SiO2 structure. A magnetodielectric (MD) parameter M.D. of 4.4% was obtained in this case. BaTiO3 nanoparticles of diameter ~25 nm having pores with diameter 10 nm showed multiferroic behavior which arose due to the presence of oxygen vacancies as a result of large surface area present. An M.D. parameter of 11% was found. Similarly mesoporous LiNbO3 of 10 nm diameter showed an M.D. parameter of ~4.5% at a magnetic field 1 Tesla. A giant magnetocapacitance effect with a value of 44% at 1.5 T was observed in nickel zinc ferrite (NZF) impregnated mesoporous silica. A magnetocapacitance of 51% at magnetic field 1.7 T was found in the case of nanocomposites comprising of iron ion containing silica based nanoglass and mesoporous silica. In the last two examples the behavior was explained on the basis of Catalan model of space-charge polarization with extracted values of magnetoresistance of the NZF and nanoglass phases being 58%.
