Static Magnetoelectric Voltage Coefficient Research Articles

Composition dependent electrical, dielectric, magnetic and magnetoelectric properties of ( x)Co 0.5Zn 0.5Fe 2O 4 + (1 − x)PLZT composites

Magnetoelectric (ME) composites of ( x)Co 0.5Zn 0.5Fe 2O 4 + (1 − x)Pb 0.93La 0.07(Zr 0.60Ti 0.40)O 3 in which x varies as 0, 0.15, 0.30, 0.45 and 1 were prepared by solid-state reaction technique. Single phase formation in x = 0 and x = 1 and two distinct phases formation in x = 0.15, 0.30 and 0.45 composites were confirmed by X-ray diffraction (XRD) technique. The backscatter mode SEM images were used to study the microstructure, average grain size and distribution of individual phases in composite. Variation of dielectric constant, loss tangent, Seebeck coefficient and magnetization were studied with changing content of individual phases at and well above room temperature. Static magnetoelectric voltage coefficient, i.e. DC (ME) H was studied as a function of DC magnetic field in the range 0–5 kOe.

Studies on dielectric and magnetoelectric behavior of 25% CMFO ferrite and 75% BZT ferroelectric multiferroic magnetoelectric composites

In the present work, multiferroic magnetoelectric (ME) composites of ferrite and ferroelectric phases are prepared. Here, the magnetostrictive (ferrite) phase, Co 1.2 − yMn yFe 1.8O 4 ( y = 0.0 to 0.4) i.e. CMFO is synthesized by chemical combustion route and the piezoelectric (ferroelectric) phase, BaZr 0.08Ti 0.92O 3 i.e. BZT is synthesized by conventional ceramic method. Frequency dependent dielectric constant measurement from 20 Hz–1 MHz at room temperature shows usual dielectric dispersion behaviour, which may be attributed to the Maxwell–Wagner type interfacial polarization. Temperature dependent dielectric constant measurement shows two dielectric maxima, one below 100 °C and the second above 500 °C. The dielectric maxima below 100 °C corresponds to the transition temperature of the ferroelectric phase and that of above 500 °C corresponds to the transition temperature of the ferrite phase of the ME composites. It is observed that as Mn content increases in the cobalt ferrite, the phase transition temperature of the ferrite phase decreases. The static magnetoelectric voltage coefficient was measured as a function of intensity of the applied dc magnetic field. These magnetoelectric composites may have possible applications in magnetic field sensing probes and linear ME devices.

Multiferroic properties of Ni ferrite—PLZT composites

Abstract The ferroelectric, magnetic and magnetoelectric properties of (x) NiFe2O4 [NFO]+(1−x) Pb0.93La0.07(Zr0.60Ti0.40)O3 [PLZT] composites, where (x=0, 0.15, 0.30, 0.45, and 1) synthesized using double sintering ceramic method were studied. Structural analysis of these composites using X-ray diffraction (XRD) techniques confirms presence of both the phases in the composite without any impurity or intermediate phase. The scanning electron microscopy (SEM) images recorded in backscattered mode was used to study the microstructure and investigate connectivity scheme in composites. Observation of well saturated ferroelectric hysteresis loops for PLZT phase and their composites, and magnetic hysteresis loops for NFO and composites samples confirms the ferroelectric and magnetic nature of the samples. The magnetoelectric (ME) coefficient (dE/dH) was noted as a function of dc magnetic field for two different orientations viz. transverse and longitudinal and different content of magnetostrictive–piezoelectric phases. Maximum value of static ME voltage coefficient obtained for transverse orientation was 8.9 mV/cm∗Oe in 15% NFO+85%PLZT bulk composites.

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.