Magnetoelectric Conversion Factor Research Articles

Lead zirconate titanate-nickel zink ferrite thick-film composites: obtaining by the screen printing technique and magnetoelectric properties

Layered thick-film composites containing one lead zirconate titanate (PZT) layer, one nickel zinc ferrite (NZF) layer, two PZT-NZF layers, or three PZT-NZF-PZT layers each 40–50 μm thick are prepared. The layers are applied by screen printing on a ceramic aluminum oxide substrate with a preformed contact (conducting) layer. The dielectric properties of the composites are studied in the temperature interval 80–900 K and the frequency interval 25 Hz-1 MHz. Polarized samples exhibit piezoelectric, pyroelectric, and magnetoelectric effects. In tangentially magnetized two- and three-layer composites, the magnetoelectric conversion factor equals 57 kV/(m T) at low frequencies and reaches 2000 kV/(m T) at the mechanical resonance frequency.

Studies on magnetic, dielectric and magnetoelectric behavior of ( x) NiFe 1.9Mn 0.1O 4 and (1 − x) BaZr 0.08Ti 0.92O 3 magnetoelectric composites

In the present research work, the magnetoelectric (ME) composites of ferrite and ferroelectric phases with ( x) NiFe 1.9Mn 0.1O 4 and (1 − x) BaZr 0.08Ti 0.92O 3 (where x = 0.10, 0.20 and 0.30) respectively were synthesized by the conventional ceramic method. The X-ray diffraction pattern of the composite reveals a spinel phase formation for the ferrite and perovskite phase formation for the ferroelectric phase without any other phase. The SEM micrographs of composites were taken to determine the average grain size and also to study the surface morphology. The effect of constituent phase variation on the B– H hysteresis behavior and the dielectric properties was examined. The dielectric constant shows usual dielectric dispersion behavior with increasing frequency which is due to the Maxwell–Wagner type surface interfacial polarization. From the ac conductivity study, it is confirmed that the conduction in the present composites is of small polaron type. The static magnetoelectric (ME) voltage coefficient developed on the surface of magnetoelectric material was measured as a function of applied dc magnetic field. The maximum ME conversion factor of 1.18 mV/cm Oe was observed for x = 0.10 composite. Such composites may be useful to fabricate the magnetic field sensors and applicable in many linear ME devices.

Electrical properties and magnetoelectric effect in(x)Ni0.5Zn0.5Fe2O4+(1−x)BPZT composites

Magneto electric (ME) composites with the composition(x)Ni0.5Zn0.5Fe2O4+(1−x)Ba0.8Pb0.2Zr0.8Ti0.2O3 (BPZT—barium lead zirconate titanate), in whichx varies as 0.0, 0.15, 0.30, 0.45, and 1.0 in molar ratio, were prepared by the conventionaldouble sintering ceramic technique. The presence of two phases, namely ferrite (Ni0.5Zn0.5Fe2O4) andferroelectric (Ba0.8Pb0.2Zr0.8Ti0.2O3), was confirmed by x-ray diffraction analysis. The DC resistivity wasmeasured as a function of temperature, and the AC conductivity (σAC) as a function of frequency (100 Hz–1 MHz). From the experimental results, it is concluded thatthe conduction in these composites is due to small polarons. The relative dielectric constantwith variation of frequency (in the range of 20 Hz–1 MHz) and temperature at four fixedfrequencies (i.e. 1 kHz, 10 kHz, 100 kHz, and 1 MHz) was studied. The hysteresis behavior wasstudied to understand the magnetic properties such as saturation magnetization (Ms) and magneticmoment (μB). The static magneto electric voltage coefficient(dE/dH)H was measured as a function of applied DC magnetic field and it increases first andthen decreases with increasing magnetic field. The variation of the ME responsewas explained in terms of the ferrite content, the resistivity of the compositesand the intensity of the magnetic field. The maximum ME conversion factor,698 μV cm−1 Oe−1, was observed forthe composite with 30% ferrite+70% ferroelectric.

Characterization and property measurements of ( y) Co 0.9Cd 0.1Fe 2O 4 + (1 − y) PZT ME composites

The ( y) Co 0.9Cd 0.1Fe 2O 4 + (1 − y) PZT ME composites where ( y = 0.15, 0.30 and 0.45) were prepared using ceramic method. The phase development, morphological changes of the samples were analyzed using XRD and SEM techniques. The results revealed that the particle size of the ferrite phase is less than that of ferroelectric phase (0.52 μm). The DC resistivity for different compositions was studied as a function of temperature. The dielectric parameters such as dielectric constant, dielectric loss and AC conductivity were studied as a function of frequency in the range 100 Hz to 1 MHz. The magnetic behavior of the samples was analyzed by hysteresis measurement. The static value of the magnetoelectric conversion factor, i.e. (d E/d H) H was measured as a function of applied magnetic field. The dependence of ME coefficient on DC resistivity is explained.

Studies on dielectric and magnetic properties of (x) Ni0.2Co0.8Fe2O4+(1−x) barium lead zirconate titanate magnetoelectric composites

The piezomagnetic (ferrite)–piezoelectric (ferroelectric) composites with compositions (x) Ni0.2Co0.8Fe2O4+(1−x) Ba0.8Pb0.2Zr0.8Ti0.2O3 [barium lead zirconate titanate (BPZT)] in which x varies as 0.0, 0.15, 0.30, 0.45, and 1.0 mol % were prepared by conventional ceramic double-sintering method. The presence of constituent phases in the composites was confirmed by x-ray diffraction studies and the average grain size was calculated by using scanning electron microscopy. The dielectric constant (ε′) and loss tangent (tan δ) were measured as a function of frequency in the frequency range 20 Hz–1 MHz. Variation of the dielectric constant and loss tangent with temperature at four fixed frequencies (1, 10, and 100 KHz and 1 MHz) was studied. The ac conductivity was studied to understand the conduction mechanism in terms of small polarons. The hysteresis behavior was studied to understand the magnetic properties such as saturation magnetization (Ms) and magnetic moment (μB). The static magnetoelectric (ME) voltage coefficient was measured as function of applied dc magnetic field and variation in ME response has been explained in terms of the content of piezomagnetic phase and the intensity of applied magnetic field. The maximum ME conversion factor of 536 μV/cm Oe was observed for 15% Ni0.2Co0.8Fe2O4+85% BPZT composite.

Effect of resistivity on magnetoelectric effect in (x)NiFe2O4–(1−x)Ba0.9Sr0.1TiO3 ME composites

Abstract The standard double sintering ceramic method was used to prepare the magnetoelectric composites having ferrite and ferroelectric phase. The coexistence of ferrite (NiFe2O4) and ferroelectric (Ba0.9Sr0.1TiO3) was confirmed by the XRD patterns and the lattice constant for each composition is calculated. SEM micrographs were taken to understand the microstructure of the samples. The dielectric constant was studied as a function of frequency in the range 100 Hz to 1 MHz. The AC conductivity as a function of frequency and DC resistivity as a function of temperature were studied for different compositions. The static value of the magnetoelectric conversion factor, i.e. (dE/dH)H was studied as a function of applied magnetic field. Lastly the dependence of Magnetoelectric effect (ME) effect on DC resistivity is shown in this paper.

Response of dielectric behaviour on ferroelectric rich ( y) Ni 0.8Zn 0.2Fe 2O 4 + (1 − y) PZT ME composites

The magnetoelectric (ME) composites consisting of ferrite and ferroelectric phases viz. ( y) Ni 0.8Zn 0.2Fe 2O 4 + (1 − y) PbZr 0.52Ti 0.48O 3 (PZT) in which y varies as 0, 0.15, 0.30, 0.45 and 1 mol% were prepared by a conventional double-sintering ceramic method. The presence of two phases in composites was confirmed by XRD technique. The variation of dielectric constant ( έ ) and loss tangent (tan δ) with frequency in the range 20 Hz–1 MHz at room temperature and also with temperature at four different frequencies (viz.1 kHz, 10 kHz, 100 kHz, and 1 MHz) were studied. The detailed studies on the dielectric properties were done presuming that the magnetoelectric interaction between constituent ferrite and ferroelectric phases may result in various anomalies in the dielectric behaviour of these composites. Ac conductivity measurements were carried out to determine the nature of charge carriers during conduction. The value of static magnetoelectric conversion factor (d E/d H) H was measured as a function of intensity of applied dc magnetic field. The maximum value of ME voltage coefficient viz. 769 μV cm −1 Oe was observed for a 15% Ni 0.8Zn 0.2Fe 2O 4 + 85% PZT composite.

Electrical properties of Ni0.93Co0.02Mn0.05Fe2O4 + BaTiO3 ME composites

Polycrystalline samples of mixed composites of Ni0.93Co0.02Mn0.05Fe2O4 + BaTiO3 were prepared by conventional double sintering ceramic method. The phase analysis was carried out by using X-ray diffraction technique. Variation of dc resistivity and thermo emf was studied as a function of temperature. AC conductivity (σac) was investigated in the frequency range 100 Hz–1 MHz. The loss tangent (tan δ) measurements conclude that the conduction mechanism in these samples is due to small polaron hopping. The magnetoelectric conversion factor, i.e. dc(ME)H was studied as a function of intensity of magnetic field and the maximum value 407 μV/cm/Oe was observed at a field of 0.8 kOe in a composite with 85% BaTiO3 and 15% Ni0.93Co0.02Mn0.05Fe2O4 phase.

Dielectric properties and magnetoelectric effect of ( x)NiFe 2O 4+(1− x)Ba 0.8Sr 0.2TiO 3 composites

Magnetoelectric composites of NiFe 2O 4 and Ba 0.8Sr 0.2TiO 3 were prepared using conventional double-sintering ceramic method. The phase formation of magnetoelectric composites was confirmed by XRD technique. Variation of dielectric constant and loss tangent at room temperature with frequency in the range 100 Hz–1 MHz has been studied. Also the variation of dielectric constant and loss tangent with temperature and composition at fixed frequencies of 1 kHz, 10 kHz, 100 kHz and 1 MHz is reported. The static value of the magnetoelectric conversion factor was measured as a function of intensity of the magnetic field. The ME voltage coefficient of about 430 μV/cm Oe was observed for 15% NiFe 2O 4+85% Ba 0.8Sr 0.2TiO 3 composite. All the samples show linear variation of magnetoelectric conversion in the presence of static magnetic field.

Studies on electrical properties of (x) BaTiO3 + (1−x) Ni0.92Co0.03Mn0.05Fe2O4 ME composites

The (1−x) Ni0.92Co0.03Mn0.05Fe2O4 + (x) BaTiO3 magnetoelectric (ME) composite have been prepared using conventional double sintering ceramic process where x varies as 1.00, 0.85, 0.70, 0.55 and 0.00. The presence of both phases has been confirmed by X-ray diffraction and the microstructure study will be carried out by SEM technique. The dc resistivity and thermo-emf of the samples have been studied with variation in temperature. The variation of dielectric constant (έ) and loss tangent (tan δ) will be measured in the frequency range 100 Hz–1 MHz. The ac conductivity has been derived from dielectric constant (έ) and loss tangent (tan δ). The static value of magnetoelectric conversion factor dc (ME)H has been studied as a function of intensity of magnetic field.

Electrical conduction, dielectric behavior and magnetoelectric effect in ( x)BaTiO 3 + (1 − x)Ni 0.94Co 0.01Mn 0.05Fe 2O 4 ME composites

Electrical and magnetoelectric properties of magnetoelectric (ME) composites containing barium titanate as electrical component and a mixed Ni-Co-Mn ferrite as the magnetic component are reported. The ME composites with a general formula ( x)BaTiO 3 + (1 − x)Ni 0.94Co 0.01Mn 0.05Fe 2O 4 where x varies as 0, 0.55, 0.70, 0.85 and 1 were prepared by standard double sintering ceramic method. The presence of both the phases was confirmed by X-ray diffraction technique. The dc resistivity was measured as a function of temperature. The variation of dielectric constant ( έ) and loss tangent (tan δ) with frequency (100 Hz–1 MHz) and with temperature was studied. The conduction is explained on the basis of small polaron model based on ac conductivity measurements. The static value of ME conversion factor i.e. dc (ME) H was studied as function of intensity of magnetic field. The changes were observed in dielectric properties as well as ME effect as the molar ratio of the components was varied. A maximum value of ME conversion factor of 610 μV/cm Oe was observed in the case of a composite containing 15 mol% ferrite phase.

Response of dielectric behavior and magnetoelectric effect in ferroelectric rich ( x) Ni 0.9Zn 0.1Fe 2O 4 + (1 − x) PZT ME composites

The magnetoelectric (ME) composites consisting of ferrite and ferroelectric phases viz. ( x) Ni 0.9Zn 0.1Fe 2O 4 + (1 − x) PbZr 0.52Ti 0.48O 3 (PZT) in which x varies as 0, 0.15, 0.30, 0.45 and 1 mol% were prepared by a conventional double-sintering ceramic method. The presence of two phases in composites was confirmed by XRD technique. The variation of dielectric constant ( έ ) with frequency in the range 20 Hz to 1 MHz at room temperature and also with temperature at four different frequencies (viz. 1 kHz, 10 kHz, 100 kHz, and 1 MHz.) were studied. The detailed studies on the dielectric properties were done presuming that the magnetoelectric interaction between the constituent phases may result in various anomalies in the dielectric behaviour of the composites. ac conductivity measurements were carried out to determine the nature of charge conduction. The hysteresis measurements were done to determine saturation magnetization ( M s) and magnetic moment ( η B). The value of static magnetoelectric conversion factor (d E/d H) H was measured as a function of intensity of applied dc magnetic field. The maximum value of ME voltage coefficient viz. 748 μV/cm Oe was observed for a 15% Ni 0.9Zn 0.1Fe 2O 4 + 85% PZT composite.

Studies on electrical properties and the magnetoelectric effect on ferroelectric-rich(x)Ni0.8Zn0.2Fe2O4+(1−x) PZT ME composites

Magnetoelectric composites with ferrite–ferroelectric composition(x)Ni0.8Zn0.2Fe2O4+(1−x) PZT (lead zirconatetitanate (PbZr0.52Ti0.48O3) used as aferroelectric phase) in which x varies as 0, 0.15, 0.30, 0.45 and 1 mol% were prepared by using a conventional ceramicdouble-sintering method. Phase analysis was carried out using the x-ray diffractiontechnique, which confirms a cubic spinel structure for the ferrite and tetragonalperovskite structure for the ferroelectric phase. The variation of the dielectric constant(ε′) and losstangent (tanδ) in the frequency range 20 Hz–1 MHz were studied. The conduction phenomenon is explainedon the basis of a small polaron hopping model. The confirmation of this phenomenonwas made with the help of ac conductivity measurements. The dc resistivity wasmeasured as a function of temperature in the range from room temperature to800 °C. Hysteresis measurements were performed to determine the saturation magnetization(Ms) and magneticmoment (ηB). The static magnetoelectric conversion factor(dE/dH)H was measured as a function of the magnetic field. All composites show a linear decrease ofmagnetoelectric conversion in the presence of a static magnetic field.

Structural analysis and electrical properties of ME composites

The magnetoelectric (ME) composites are obtained by binding a magnetostrictive phase with piezoelectric phase so as to obtain the magnetoelectric output. The magnetoelectric composites with a general formula ( x) BaTiO 3 + (1 − x) Ni 0.92Co 0.03Mn 0.05Fe 2O 4 in which x varies as 0.85, 0.70 and 0.55 were prepared by standard double sintering ceramic method. The structural analysis was carried out to confirm the presence of two phases in composites. The dc resistivity ( ρ dc) was measured as a function of temperature in the range 300–800 K. The variation of resistivity with temperature shows semiconducting behaviour. The variation of dielectric constant and dielectric loss in the frequency range 100 Hz–1 MHz was studied. The conduction is explained on the basis of small polaron model. The confirmation of this phenomenon was made with the help of ac conductivity measurements. The hysteresis measurements were carried out to determine saturation magnetization (Ms) and coercivity (Hc). The variation of saturation magnetization and magnetic moment ( μ B) is interpreted in terms of composition. The static magnetoelectric conversion factor (d E/d H) was measured as a function of dc magnetic field. The maximum value of d E/d H was found to be 354 μV/cm. Oe for a composite with x = 0.85.

Structural, dielectric and magnetoelectric effect in (x)BaTiO3 + (1 − x)Ni0.93Co0.02Mn0.05Fe2O4 ME composites

Magnetoelectric composites with composition (x)BaTiO3+(1−x)Ni0.93Co0.02Mn0.05Fe2O4 in which x varies as 1.00, 0.85, 0.70, 0.55 and 0.00 in molar percent were prepared by conventional double sintering ceramic method. The structural analysis carried out by X-ray diffraction technique has confirmed that both phases are present in all the composites. The dc resistivity was measured as a function of temperature ranging from room temperature to 500°C. The dielectric constant and dielectric loss was studied as a function of frequency and temperature. The saturation magnetization (Ms) and magnetic moment (ηB) in Bohr magneton were calculated from magnetic hysteresis loop. The static value of the magnetoelectric conversion factor, i.e., dc(ME)H was studied as a function of dc magnetic field. A large ME voltage coefficient of about 407μV/cmOe was observed for 15% Ni0.93Co0.02Mn0.05Fe2O4+85% BaTiO3 ME composites. All the samples show linear magnetoelectric conversion in the presence of static magnetic field.

Magnetic properties and dielectric behavior in ferrite/ferroelectric particulate composites

Particulate composites of ferrite and ferroelectric phases having the general formula ( x)BaTiO 3+(1– x)Ni 0.92Co 0.03Cu 0.05Fe 2O 4 (where x is mole fraction of components that varies as 0.85, 0.70 and 0.55) were prepared by conventional double-sintering ceramic method. The presence of constituent phases was confirmed by X-ray diffraction (XRD) technique. The average grain size was determined by using scanning electron micrographs. The variation of dielectric constant and tan δ with frequency in the range 20 Hz–1 MHz was studied. The variation of loss tangent (tan δ) and dielectric constant with temperature at fixed frequencies of 1 kHz, 10 kHz, 100 kHz and 1 MHz was also studied. The saturation magnetization ( M s) and magnetic moment ( η B in Bohr magnetons) are reported for all composites. The static magnetoelectric (ME) voltage coefficient was measured as a function of intensity of applied DC magnetic field. The changes were observed in dielectric properties as well as in ME output with variation in molar fraction of constituent phases. A maximum ME conversion factor of 538.59 μV/cm G was observed for the composites with 70% BaTiO 3+30% Ni 0.92Co 0.03Cu 0.05Fe 2O 4. The present ME composites may be useful in preparing devices such as magnetic sensors and cables, etc.

Effect of composition on coupled electric, magnetic, and dielectric properties of two phase particulate magnetoelectric composite

The particulate composite materials of ferrite-ferroelectric ceramics viz. nickel-cobalt-copper ferrite (i.e., Ni0.94Co0.01Cu0.05Fe2O4) and barium titanate were synthesized by the double sintering ceramic technique. The presence of constituent phases in the composites was confirmed by x-ray diffraction studies. The average grain size was calculated by using a scanning electron micrograph. The electrical properties such as dc resistivity and thermo-emf were measured as a function of temperature and volume fraction of constituent phases. The ac conductivity was calculated from dielectric data in the frequency range from 100Hzto1MHz. It is concluded that the conduction in the present composites is due to small polarons. The relative dielectric constant measured as a function of applied frequency varies with the variation in the dc resistivity and molar fraction of constituent phases. It shows dispersion in the lower frequency range. The hysteresis behavior was studied to understand the magnetic properties such as saturation magnetization (Ms) and magnetic moment (μB). The static magnetoelectric (ME) voltage coefficient was measured as a function of applied dc magnetic field. It increases first and then falls down with increasing magnetic field. The variation in ME response has been explained in terms of content of ferrite phase, resistivity of composites, and intensity of magnetic field. The maximum ME conversion factor of 637μV∕cmOe was observed for the composite with 30% Ni0.94Co0.01Cu0.05Fe2O4+70% BaTiO3. These composites may be useful as phase shifters, magnetic sensors, cables, etc.

Electrical conduction and magnetoelectric effect in ferroelectric rich ( x)Ni 0.9Zn 0.1Fe 2O 4 + (1 − x)PZT ME composites

Magnetoelectric composites with ferrite–ferroelectric compositions ( x)Ni 0.9Zn 0.1Fe 2O 4 + (1 − x)PZT in which x varies as 0, 0.15, 0.30, 0.45 and 1 mol% were prepared by using a conventional ceramic double-sintering method. The phase analysis was carried out using X-ray diffraction technique, which confirms that there is no any intermediate phases present in the composites. The variation of dielectric constant ( ε ˙ ) and loss tangent (tan δ) in the frequency range 20 Hz to 1 MHz was studied. The conduction phenomenon was explained on the basis of a small polaron hopping model. The confirmation of this phenomenon was made with the help of ac conductivity measurements. The dc resistivity was measured as a function of temperature in the temperature range from 300 to 800 °C. Static magnetoelectric conversion factor (d E/d H) H was measured as a function of magnetic field. All composites show linear decrease of magnetoelectric conversion in the presence of static magnetic field.

Complex impedance analyses and magnetoelectric effect in ferrite–ferroelectric composite ceramics

Abstract Magnetoelectric (ME) composites y Ba 0.8 Pb 0.2 TiO 3 –( 1 − y )CuFe 2 O 4 are prepared by ceramic method. The component phases are prepared from two different routes, viz. CuFe 2 O 4 (ferrite phase) is prepared by oxalate precursor route and Ba 0.8 Pb 0.2 TiO 3 (ferroelectric phase) by solid-state reaction route. No intermediate phases are observed in the composites containing these ferrite and ferroelectric phases. ME conversion factor (measure of ME effect) is found to be enhanced compared to those reported in the composites, in which the component phases were prepared by only one route, i.e. solid-state reaction route. The results on ME conversion are well accounted by measuring the complex impedance and analyzing their Nyquist plots.

Electrical conduction and magnetoelectric effect of (x) BaTiO3 + (1−x) Ni0.92Co0.03Cu0.05Fe2O4 composites in ferroelectric rich region

Particulate composites with composition (x)BaTiO3+(1−x)Ni0.92Co0.03Cu0.05Fe2O4 in which x varies as 1, 0.85, 0.70, 0.55 and 0 (in mol%) were prepared by the conventional double sintering ceramic technique. The presence of two phases viz. ferromagnetic (Ni0.92Co0.03Cu0.05Fe2O4) and ferroelectric (BaTiO3) was confirmed by X-ray diffraction analysis. The dc resistivity and thermo-emf measurements were carried out with variation of temperature. The ac conductivity (σac) measurements investigated in the frequency range 100 Hz to 1 MHz conclude that the conduction in these composites is due to small polarons. The variation of dielectric constant and loss tangent with frequency (20 Hz to 1 MHz) was studied. The static magnetoelectric conversion factor, i.e. dc (dE/dH)H was measured as a function of intensity of applied magnetic field. The changes were observed in electrical properties as well as in magnetoelectric voltage coefficient as the molar ratio of the constituent phases was varied. A maximum value of magnetoelectric conversion factor of 536.06 μV/cm Oe was observed for the composite with 70% BaTiO3+30% Ni0.92Co0.03Cu0.05Fe2O4 at a dc magnetic field of 2.3 K Oe. The maximum magnetoelectric conversion output has been explained in terms of ferrite-ferroelectric content, applied static magnetic field and resistivity.