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G. Srinivasan - One of the best experts on this subject based on the ideXlab platform.
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Ferrite-Piezoelectric Multilayers for Magnetic Field Sensors
IEEE Sensors Journal, 2006Co-Authors: Y K Fetisov, A.y. Ostashchenko, K. E. Kamentsev, A.a. Bush, G. SrinivasanAbstract:A magnetic field sensor based on magnetoelectric effects in a Ferrite-piezoelectric layered sample is proposed. Such sensors are passive, provide direct conversion of magnetic fields into an electrical signal, and allow measurements of both ac and dc magnetic fields. A multilayer sample of nickel zinc Ferrite-lead zirconate titanate has been used to characterize the sensor response to ac and dc fields, field orientations, frequency, and temperature. The sample shows a linear response for dc fields up to a maximum of 1750 Oe. The sensor output is temperature independent over 273-337 K, but is dependent on frequency of the ac excitation field. Operating at electromechanical resonance for the element enhances the sensor sensitivity by an order of magnitude. For ac magnetic field sensors, the output varies linearly with amplitude
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magnetoelectric interactions in hot pressed nickel zinc Ferrite and lead zirconante titanate composites
Applied Physics Letters, 2004Co-Authors: G. Srinivasan, V M Laletsin, Christopher P Devreugd, C S Flattery, N PaddubnayaAbstract:The synthesis by hot pressing and wide-band (10Hz–1MHz) magnetoelectric (ME) characterization of bulk composites of nickel zinc Ferrite Ni1−xZnxFe2O4 (NZFO) (x=0–0.5) and lead zirconate titanate (PZT) are reported. Hot-pressed samples show an order of magnitude improvement in ME voltage coefficient compared to sintered samples. Frequency dependence of ME coefficients show a three order of magnitude enhancement at electromechanical resonance. The ME coupling is maximum for samples with equal volume of Ferrite and PZT. The strongest ME interactions are measured for samples of NZFO (x=0.2) and PZT.
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magnetoelectric effects in Ferrite lead zirconate titanate layered composites the influence of zinc substitution in Ferrites
Physical Review B, 2003Co-Authors: G. Srinivasan, E T Rasmussen, R HayesAbstract:The observation of strong magnetoelectric (ME) coupling is reported in zinc-substituted layered composites of Ferrites and lead zirconate titanate (PZT). Multilayer samples contained cobalt zinc Ferrite Co 1 - x Zn x Fe 2 O 4 (CZFO) (x=0-0.6) or nickel zinc Ferrite Ni 1 - x Zn x Fe 2 O 4 (NZFO) (x=0-0.5) and were prepared by laminating and sintering Ferrite and PZT thick films obtained by tape casting. The ME voltage coefficient α E was measured for transverse and longitudinal field orientations for frequencies 10-1000 Hz. A substantial enhancement in α E is observed with the substitution of Zn. The largest increase, by about 500%, is observed in CZFO-PZT and the smallest increase of 60% is measured for NZFO-PZT. As the Zn concentration is increased, α E increases and shows a maximum for x=0.2-0.4, depending on the Ferrite. The data is analyzed based on a theoretical model for a Ferrite-PZT bilayer, taking into consideration less than ideal coupling at the interface. The interface coupling parameter k is quite small for CZFO-PZT; it increases from 0 to 0.6 as Zn concentration is increased from 0% to 40%. Composites of NZFO-PZT, however, have a near perfect interface coupling. The Zn-assisted enhancement in the ME coefficient is discussed in terms of joule magnetostriction, initial permeability, and magnetomechanical coupling for the Ferrites.
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magnetoelectric effects in Ferrite lead zirconate titanate layered composites the influence of zinc substitution in Ferrites
Physical Review B, 2003Co-Authors: G. Srinivasan, E T Rasmussen, R HayesAbstract:The observation of strong magnetoelectric (ME) coupling is reported in zinc-substituted layered composites of Ferrites and lead zirconate titanate (PZT). Multilayer samples contained cobalt zinc Ferrite ${\mathrm{Co}}_{1\ensuremath{-}x}{\mathrm{Zn}}_{x}{\mathrm{Fe}}_{2}{\mathrm{O}}_{4}$ (CZFO) $(x=0--0.6)$ or nickel zinc Ferrite ${\mathrm{Ni}}_{1\ensuremath{-}x}{\mathrm{Zn}}_{x}{\mathrm{Fe}}_{2}{\mathrm{O}}_{4}$ (NZFO) $(x=0--0.5)$ and were prepared by laminating and sintering Ferrite and PZT thick films obtained by tape casting. The ME voltage coefficient ${\ensuremath{\alpha}}_{E}$ was measured for transverse and longitudinal field orientations for frequencies 10--1000 Hz. A substantial enhancement in ${\ensuremath{\alpha}}_{E}$ is observed with the substitution of Zn. The largest increase, by about 500%, is observed in CZFO-PZT and the smallest increase of 60% is measured for NZFO-PZT. As the Zn concentration is increased, ${\ensuremath{\alpha}}_{E}$ increases and shows a maximum for $x=0.2--0.4,$ depending on the Ferrite. The data is analyzed based on a theoretical model for a Ferrite-PZT bilayer, taking into consideration less than ideal coupling at the interface. The interface coupling parameter k is quite small for CZFO-PZT; it increases from 0 to 0.6 as Zn concentration is increased from 0% to 40%. Composites of NZFO-PZT, however, have a near perfect interface coupling. The Zn-assisted enhancement in the ME coefficient is discussed in terms of joule magnetostriction, initial permeability, and magnetomechanical coupling for the Ferrites.
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giant magnetoelectric effects in layered composites of nickel zinc Ferrite and lead zirconate titanate
Solid State Communications, 2002Co-Authors: G. Srinivasan, E T Rasmussen, R Hayes, V M Laletsin, N Puddubnaya, D J FekelAbstract:Abstract A 40-fold increase in the strength of magnetoelectric (ME) coupling is reported in layered samples of nickel Ferrite (NFO)–lead zirconate titanate (PZT) compared to bulk composites. In bulk samples, the transverse and longitudinal couplings are weak and are of equal magnitude. The ME coupling strengthens by an order of magnitude when high-resistivity modified-NFO is used in the composite. A further enhancement of ME interactions is accomplished in bilayer and multilayer structures of Ni1−xZnxFe2O4(x=0–0.5)–PZT. The coupling is dependent on Zn substitution, with x=0.2 showing the strongest ME interaction. These observations are in good agreement with theory.
R Hayes - One of the best experts on this subject based on the ideXlab platform.
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magnetoelectric effects in Ferrite lead zirconate titanate layered composites the influence of zinc substitution in Ferrites
Physical Review B, 2003Co-Authors: G. Srinivasan, E T Rasmussen, R HayesAbstract:The observation of strong magnetoelectric (ME) coupling is reported in zinc-substituted layered composites of Ferrites and lead zirconate titanate (PZT). Multilayer samples contained cobalt zinc Ferrite Co 1 - x Zn x Fe 2 O 4 (CZFO) (x=0-0.6) or nickel zinc Ferrite Ni 1 - x Zn x Fe 2 O 4 (NZFO) (x=0-0.5) and were prepared by laminating and sintering Ferrite and PZT thick films obtained by tape casting. The ME voltage coefficient α E was measured for transverse and longitudinal field orientations for frequencies 10-1000 Hz. A substantial enhancement in α E is observed with the substitution of Zn. The largest increase, by about 500%, is observed in CZFO-PZT and the smallest increase of 60% is measured for NZFO-PZT. As the Zn concentration is increased, α E increases and shows a maximum for x=0.2-0.4, depending on the Ferrite. The data is analyzed based on a theoretical model for a Ferrite-PZT bilayer, taking into consideration less than ideal coupling at the interface. The interface coupling parameter k is quite small for CZFO-PZT; it increases from 0 to 0.6 as Zn concentration is increased from 0% to 40%. Composites of NZFO-PZT, however, have a near perfect interface coupling. The Zn-assisted enhancement in the ME coefficient is discussed in terms of joule magnetostriction, initial permeability, and magnetomechanical coupling for the Ferrites.
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magnetoelectric effects in Ferrite lead zirconate titanate layered composites the influence of zinc substitution in Ferrites
Physical Review B, 2003Co-Authors: G. Srinivasan, E T Rasmussen, R HayesAbstract:The observation of strong magnetoelectric (ME) coupling is reported in zinc-substituted layered composites of Ferrites and lead zirconate titanate (PZT). Multilayer samples contained cobalt zinc Ferrite ${\mathrm{Co}}_{1\ensuremath{-}x}{\mathrm{Zn}}_{x}{\mathrm{Fe}}_{2}{\mathrm{O}}_{4}$ (CZFO) $(x=0--0.6)$ or nickel zinc Ferrite ${\mathrm{Ni}}_{1\ensuremath{-}x}{\mathrm{Zn}}_{x}{\mathrm{Fe}}_{2}{\mathrm{O}}_{4}$ (NZFO) $(x=0--0.5)$ and were prepared by laminating and sintering Ferrite and PZT thick films obtained by tape casting. The ME voltage coefficient ${\ensuremath{\alpha}}_{E}$ was measured for transverse and longitudinal field orientations for frequencies 10--1000 Hz. A substantial enhancement in ${\ensuremath{\alpha}}_{E}$ is observed with the substitution of Zn. The largest increase, by about 500%, is observed in CZFO-PZT and the smallest increase of 60% is measured for NZFO-PZT. As the Zn concentration is increased, ${\ensuremath{\alpha}}_{E}$ increases and shows a maximum for $x=0.2--0.4,$ depending on the Ferrite. The data is analyzed based on a theoretical model for a Ferrite-PZT bilayer, taking into consideration less than ideal coupling at the interface. The interface coupling parameter k is quite small for CZFO-PZT; it increases from 0 to 0.6 as Zn concentration is increased from 0% to 40%. Composites of NZFO-PZT, however, have a near perfect interface coupling. The Zn-assisted enhancement in the ME coefficient is discussed in terms of joule magnetostriction, initial permeability, and magnetomechanical coupling for the Ferrites.
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giant magnetoelectric effects in layered composites of nickel zinc Ferrite and lead zirconate titanate
Solid State Communications, 2002Co-Authors: G. Srinivasan, E T Rasmussen, R Hayes, V M Laletsin, N Puddubnaya, D J FekelAbstract:Abstract A 40-fold increase in the strength of magnetoelectric (ME) coupling is reported in layered samples of nickel Ferrite (NFO)–lead zirconate titanate (PZT) compared to bulk composites. In bulk samples, the transverse and longitudinal couplings are weak and are of equal magnitude. The ME coupling strengthens by an order of magnitude when high-resistivity modified-NFO is used in the composite. A further enhancement of ME interactions is accomplished in bilayer and multilayer structures of Ni1−xZnxFe2O4(x=0–0.5)–PZT. The coupling is dependent on Zn substitution, with x=0.2 showing the strongest ME interaction. These observations are in good agreement with theory.
Sangeeta Thakur - One of the best experts on this subject based on the ideXlab platform.
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nickel zinc Ferrite from reverse micelle process structural and magnetic properties mossbauer spectroscopy characterization
Journal of Physical Chemistry C, 2009Co-Authors: Sangeeta Thakur, S C Katyal, Ajay Gupta, V R Reddy, S K Sharma, M Knobel, Mahavir SinghAbstract:Nickel−zinc Ferrite (Ni0.58Zn0.42Fe2O4) nanoparticles with an average crystallite size of about 8.4 nm were synthesized by reverse micelle technique. Bulk sample was prepared by annealing nickel−zinc Ferrite (NZFO) nanoparticles at 1473 K. Room temperature Mossbauer spectra of NZFO nanoparticles exhibit collective magnetic excitations, while annealed (bulk) NZFO particles have the ferrimagnetic phase. At 5 K, the broad shape of Mossbauer spectral lines for nanoparticles in comparison to bulk particles provide clear evidence of a wide distribution of magnetic fields acting at the Fe3+ nuclei in the nanoparticles. Bulk NZFO particles and inner core of nanoparticles exhibit a fully inverse spinel structure with a Neel type collinear spin arrangement, whereas the major feature of the ionic and spin configuration in the grain boundary (surface) region are a nonequilibrium cation distribution and a canted spin arrangement. The cation distribution of nano and bulk particles has been studied by using in-field Mos...
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room temperature ferromagnetic ordering in indium substituted nano nickel zinc Ferrite
Journal of Applied Physics, 2009Co-Authors: Sangeeta Thakur, S C Katyal, Ajay Gupta, V R Reddy, M SinghAbstract:Nano-Nickel-Zinc-indium Ferrite (NZIFO)(Ni0.58Zn0.42InxFe2−xO4) with varied quantities of indium (x=0,0.1,0.2) have been synthesized via reverse micelle technique. X-ray diffraction and transmission electron microscopy confirmed the size, structure, and morphology of the nanoFerrites. The addition of indium in Nickel-Zinc Ferrite (NZFO) has been shown to play a crucial role in enhancing the magnetic properties. Room temperature Mossbauer spectra revealed that the nano-NZFO Ferrite exhibit collective magnetic excitations, while indium doped NZFO samples have the ferromagnetic phase. The dependence of Mossbauer parameters, viz. isomer shift, quadrupole splitting, linewidth, and hyperfine magnetic field, on In3+ concentration has been studied. Mossbauer study on these nanosystems shows that the cation distribution not only depends on the particle size but also on the preparation route. Mossbauer results are also supported by magnetization data. Well defined sextets and appearance of hysteresis at room temper...
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structural and magnetic properties of nano nickel zinc Ferrite synthesized by reverse micelle technique
Journal of Magnetism and Magnetic Materials, 2009Co-Authors: Sangeeta Thakur, S C Katyal, Mahavir SinghAbstract:Abstract Nanocrystalline nickel–zinc Ferrites (Ni0.58Zn0.42Fe2O4) at different pH values (less than 9.6, 9.6, 10.96, and 11.40) for the alkali-precipitating reaction were synthesized by reverse micelle technique. X-ray diffraction reveals a well-defined nickel–zinc Ferrite crystal phase at pH=9.6. Increase in pH value obstructs pure-phase formation and results in partial formation of α-Fe2O3. The magnetic behaviour of the samples was studied by superconducting quantum interference device. All the samples show superparamagnetic behaviour at room temperature (300 K) and negligible hysteresis at low temperature (5 K). The low value of saturation magnetization is explained on the basis of spin canting. The high-field irreversibility and shifting of the hysteresis loop detected in single-phase sample has been assigned to a spin-disordered phase, which has a spin-freezing temperature of approximately 42 K and other two samples have an antiferromagnetic phase (α-Fe2O3) coupled to the ferromagnetic phase.
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improvement in electric and dielectric properties of nanoFerrite synthesized via reverse micelle technique
Applied Physics Letters, 2007Co-Authors: Sangeeta Thakur, S C Katyal, Mahendra SinghAbstract:Nano nickel zinc Ferrite (Ni0.58Zn0.42Fe2O4) with fascinating dielectric properties which reveal a direction for application was synthesized by reverse micelle technique. Dielectric constant and dielectric losses are controlled up to a measurement temperature of around 473K at higher frequency range of 9–19MHz. The dielectric loss of the sample investigated at room temperature is only 0.003 at 19MHz. The presently studied nanoFerrite also exhibits a high value of dc resistivity, 108Ωcm. High resistivity and low dielectric constant and loss can be corelated to small grain size and better compositional stoichiometry obtained as a result of processing via reverse micelle technique at low sintering temperature (773K).
E T Rasmussen - One of the best experts on this subject based on the ideXlab platform.
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magnetoelectric effects in Ferrite lead zirconate titanate layered composites the influence of zinc substitution in Ferrites
Physical Review B, 2003Co-Authors: G. Srinivasan, E T Rasmussen, R HayesAbstract:The observation of strong magnetoelectric (ME) coupling is reported in zinc-substituted layered composites of Ferrites and lead zirconate titanate (PZT). Multilayer samples contained cobalt zinc Ferrite Co 1 - x Zn x Fe 2 O 4 (CZFO) (x=0-0.6) or nickel zinc Ferrite Ni 1 - x Zn x Fe 2 O 4 (NZFO) (x=0-0.5) and were prepared by laminating and sintering Ferrite and PZT thick films obtained by tape casting. The ME voltage coefficient α E was measured for transverse and longitudinal field orientations for frequencies 10-1000 Hz. A substantial enhancement in α E is observed with the substitution of Zn. The largest increase, by about 500%, is observed in CZFO-PZT and the smallest increase of 60% is measured for NZFO-PZT. As the Zn concentration is increased, α E increases and shows a maximum for x=0.2-0.4, depending on the Ferrite. The data is analyzed based on a theoretical model for a Ferrite-PZT bilayer, taking into consideration less than ideal coupling at the interface. The interface coupling parameter k is quite small for CZFO-PZT; it increases from 0 to 0.6 as Zn concentration is increased from 0% to 40%. Composites of NZFO-PZT, however, have a near perfect interface coupling. The Zn-assisted enhancement in the ME coefficient is discussed in terms of joule magnetostriction, initial permeability, and magnetomechanical coupling for the Ferrites.
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magnetoelectric effects in Ferrite lead zirconate titanate layered composites the influence of zinc substitution in Ferrites
Physical Review B, 2003Co-Authors: G. Srinivasan, E T Rasmussen, R HayesAbstract:The observation of strong magnetoelectric (ME) coupling is reported in zinc-substituted layered composites of Ferrites and lead zirconate titanate (PZT). Multilayer samples contained cobalt zinc Ferrite ${\mathrm{Co}}_{1\ensuremath{-}x}{\mathrm{Zn}}_{x}{\mathrm{Fe}}_{2}{\mathrm{O}}_{4}$ (CZFO) $(x=0--0.6)$ or nickel zinc Ferrite ${\mathrm{Ni}}_{1\ensuremath{-}x}{\mathrm{Zn}}_{x}{\mathrm{Fe}}_{2}{\mathrm{O}}_{4}$ (NZFO) $(x=0--0.5)$ and were prepared by laminating and sintering Ferrite and PZT thick films obtained by tape casting. The ME voltage coefficient ${\ensuremath{\alpha}}_{E}$ was measured for transverse and longitudinal field orientations for frequencies 10--1000 Hz. A substantial enhancement in ${\ensuremath{\alpha}}_{E}$ is observed with the substitution of Zn. The largest increase, by about 500%, is observed in CZFO-PZT and the smallest increase of 60% is measured for NZFO-PZT. As the Zn concentration is increased, ${\ensuremath{\alpha}}_{E}$ increases and shows a maximum for $x=0.2--0.4,$ depending on the Ferrite. The data is analyzed based on a theoretical model for a Ferrite-PZT bilayer, taking into consideration less than ideal coupling at the interface. The interface coupling parameter k is quite small for CZFO-PZT; it increases from 0 to 0.6 as Zn concentration is increased from 0% to 40%. Composites of NZFO-PZT, however, have a near perfect interface coupling. The Zn-assisted enhancement in the ME coefficient is discussed in terms of joule magnetostriction, initial permeability, and magnetomechanical coupling for the Ferrites.
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giant magnetoelectric effects in layered composites of nickel zinc Ferrite and lead zirconate titanate
Solid State Communications, 2002Co-Authors: G. Srinivasan, E T Rasmussen, R Hayes, V M Laletsin, N Puddubnaya, D J FekelAbstract:Abstract A 40-fold increase in the strength of magnetoelectric (ME) coupling is reported in layered samples of nickel Ferrite (NFO)–lead zirconate titanate (PZT) compared to bulk composites. In bulk samples, the transverse and longitudinal couplings are weak and are of equal magnitude. The ME coupling strengthens by an order of magnitude when high-resistivity modified-NFO is used in the composite. A further enhancement of ME interactions is accomplished in bilayer and multilayer structures of Ni1−xZnxFe2O4(x=0–0.5)–PZT. The coupling is dependent on Zn substitution, with x=0.2 showing the strongest ME interaction. These observations are in good agreement with theory.
S C Katyal - One of the best experts on this subject based on the ideXlab platform.
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nickel zinc Ferrite from reverse micelle process structural and magnetic properties mossbauer spectroscopy characterization
Journal of Physical Chemistry C, 2009Co-Authors: Sangeeta Thakur, S C Katyal, Ajay Gupta, V R Reddy, S K Sharma, M Knobel, Mahavir SinghAbstract:Nickel−zinc Ferrite (Ni0.58Zn0.42Fe2O4) nanoparticles with an average crystallite size of about 8.4 nm were synthesized by reverse micelle technique. Bulk sample was prepared by annealing nickel−zinc Ferrite (NZFO) nanoparticles at 1473 K. Room temperature Mossbauer spectra of NZFO nanoparticles exhibit collective magnetic excitations, while annealed (bulk) NZFO particles have the ferrimagnetic phase. At 5 K, the broad shape of Mossbauer spectral lines for nanoparticles in comparison to bulk particles provide clear evidence of a wide distribution of magnetic fields acting at the Fe3+ nuclei in the nanoparticles. Bulk NZFO particles and inner core of nanoparticles exhibit a fully inverse spinel structure with a Neel type collinear spin arrangement, whereas the major feature of the ionic and spin configuration in the grain boundary (surface) region are a nonequilibrium cation distribution and a canted spin arrangement. The cation distribution of nano and bulk particles has been studied by using in-field Mos...
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room temperature ferromagnetic ordering in indium substituted nano nickel zinc Ferrite
Journal of Applied Physics, 2009Co-Authors: Sangeeta Thakur, S C Katyal, Ajay Gupta, V R Reddy, M SinghAbstract:Nano-Nickel-Zinc-indium Ferrite (NZIFO)(Ni0.58Zn0.42InxFe2−xO4) with varied quantities of indium (x=0,0.1,0.2) have been synthesized via reverse micelle technique. X-ray diffraction and transmission electron microscopy confirmed the size, structure, and morphology of the nanoFerrites. The addition of indium in Nickel-Zinc Ferrite (NZFO) has been shown to play a crucial role in enhancing the magnetic properties. Room temperature Mossbauer spectra revealed that the nano-NZFO Ferrite exhibit collective magnetic excitations, while indium doped NZFO samples have the ferromagnetic phase. The dependence of Mossbauer parameters, viz. isomer shift, quadrupole splitting, linewidth, and hyperfine magnetic field, on In3+ concentration has been studied. Mossbauer study on these nanosystems shows that the cation distribution not only depends on the particle size but also on the preparation route. Mossbauer results are also supported by magnetization data. Well defined sextets and appearance of hysteresis at room temper...
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structural and magnetic properties of nano nickel zinc Ferrite synthesized by reverse micelle technique
Journal of Magnetism and Magnetic Materials, 2009Co-Authors: Sangeeta Thakur, S C Katyal, Mahavir SinghAbstract:Abstract Nanocrystalline nickel–zinc Ferrites (Ni0.58Zn0.42Fe2O4) at different pH values (less than 9.6, 9.6, 10.96, and 11.40) for the alkali-precipitating reaction were synthesized by reverse micelle technique. X-ray diffraction reveals a well-defined nickel–zinc Ferrite crystal phase at pH=9.6. Increase in pH value obstructs pure-phase formation and results in partial formation of α-Fe2O3. The magnetic behaviour of the samples was studied by superconducting quantum interference device. All the samples show superparamagnetic behaviour at room temperature (300 K) and negligible hysteresis at low temperature (5 K). The low value of saturation magnetization is explained on the basis of spin canting. The high-field irreversibility and shifting of the hysteresis loop detected in single-phase sample has been assigned to a spin-disordered phase, which has a spin-freezing temperature of approximately 42 K and other two samples have an antiferromagnetic phase (α-Fe2O3) coupled to the ferromagnetic phase.
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improvement in electric and dielectric properties of nanoFerrite synthesized via reverse micelle technique
Applied Physics Letters, 2007Co-Authors: Sangeeta Thakur, S C Katyal, Mahendra SinghAbstract:Nano nickel zinc Ferrite (Ni0.58Zn0.42Fe2O4) with fascinating dielectric properties which reveal a direction for application was synthesized by reverse micelle technique. Dielectric constant and dielectric losses are controlled up to a measurement temperature of around 473K at higher frequency range of 9–19MHz. The dielectric loss of the sample investigated at room temperature is only 0.003 at 19MHz. The presently studied nanoFerrite also exhibits a high value of dc resistivity, 108Ωcm. High resistivity and low dielectric constant and loss can be corelated to small grain size and better compositional stoichiometry obtained as a result of processing via reverse micelle technique at low sintering temperature (773K).