Function Of Dc Magnetic Field Research Articles

Fabrication of compact circular ring antenna loaded with Gd-YIG ferrites: Photon–magnon interaction

In telecommunications technology, transmitting and receiving signals is not possible without an integrated antenna. Recently, novel approaches of transmitting and receiving signals using advancement in quantum technology as “information coherent transfer” have been emphasized which overcomes the limitations of superconducting qubits. In the present investigation, a compact-sized circular-ring antenna was designed for a 12 GHz centre frequency. The antenna was topped with Gd(x)-doped YIG (x = 0.0, 0.1, 0.2, 0.3) thin disks to investigate its tunable operation over the tri-band (C to Ku) frequencies due to the photon–magnon coupling, which enables coherent qubit information transmission from an electromagnetic (EM) carrier to the magnons. The proposed prototype of the antenna is validated using HFSS simulation. To characterize the frequency tunability of the designed antenna, we measured the return loss (S11) via a vector network analyzer as a function of dc magnetic field. Different concentrations of Gd-doped YIG ferrites (Gdx-YIG) have been loaded on ring antennas to observe strong anti-crossing phenomena with the application of an external magnetic field. The designed antenna has a tunability of around 300% for a small applied magnetic field up to 3.7 kOe. The maximum gain of dual resonance antenna is 1.4 for higher magnetic field of 3.7 kOe. The highest efficiency and lowest bandwidth of 30% and 14% respectively, for Gd0.1-YIG disk are observed. The measured normal mode splitting spectrum as a function of bias magnetic field that gives the maximum coupling strength is 153 MHz for a Gd concentration of 0.1. For practical applications, such antennas are suitable for use in tunable tri-band or multi-band applications (C to Ku).

Microwave magnetoabsorption in R0.6Sr0.4MnO3 (R = Pr and Nd)

We report microwave (MW) magnetoabsorption (ΔP) at room temperature in R0.6Sr0.4MnO3 (R = Pr and Nd) samples. ΔP as a function of dc magnetic field (− 2.5 kOe ≤ Hdc ≤ 2.5 kOe) was measured for a broad frequency range ( f = 0.1–4 GHz) of an MW magnetic field using a vector network analyzer and a copper strip coil which encloses one of the above samples. As the external dc magnetic field decreased from the maximum value, ΔP initially increases and shows a maximum for a critical field and then decreases as the field approaches zero. The critical field value increases with increasing frequency of the MW signal. Line shape analysis of the obtained spectra suggests that the observed features in ΔP are caused by ferromagnetic resonance in R = Pr and electron paramagnetic resonance in R = Nd samples, which were later confirmed using a coplanar waveguide-based broadband magnetic resonance spectrometer.

Possibilities of the application magnetoelectric current sensor for the power supply in transport systems

The paper presents the review of the magnetoelectric current sensors. The possibility of output voltage measurement of the sensor in the function of DC magnetic field is also presented.

Magnetoelastic Sensor Studies on Amorphous Magnetic FeSiB Wire and the Application in Viscosity Measurement

In this work, possible use of FeSiB amorphous magnetic wire as a magnetoelastic sensor was investigated. As-received wire did not show any magnetoelastic change. But, the wire annealed in a furnace at 465 ∘C for various times showed good magnetoelastic change. A very large change in the resonance frequency of annealed FeSiB wire as a function of DC magnetic field was obtained. This large change was explained on the basis of the high value of magnetostriction of FeSiB wire and the increase in the rotational magnetization process. It was also found that resonance frequency of FeSiB wire changes when the wire was in a liquid with different viscosities.

Study of xCo0.8Ni0.2Fe2O4+(1−x) Pb0.99625 La0.0025Zr0.55Ti0.45O3 magnetoelectric composites

We are reporting here, the studies of the structural, dielectric, ferroelectric and magnetic properties of magnetoelectric composites of La modified lead zirconate titanate (PLZT) and Ni modified cobalt ferrite (CNFO) with compositional formula xCo0.8Ni0.2Fe2O4+(1−x) Pb0.99625La0.0025Zr0.55Ti0.45O3 (x=0.00, 0.05, 0.10, 0.15 and 1.00 by weight) prepared by the solid state reaction method. Coexistence of both the phases in composites was confirmed by X-Ray diffraction technique. The microstructure and average grain size were determined from Scanning Electron Micrograph (SEM) in backscattered mode. Both the phases could be observed clearly. The variations of dielectric properties with frequency and temperature were also studied. P–E and M–H hysteresis measurements were carried. Magnetoelectric coupling (ME) coefficient for samples with x=0.05 and 0.10 were measured as a function of DC magnetic field. Maximum value of ME coefficient (1.2mV/cmOe) and piezoelectric coefficient (96 pC/N) for x=0.05 were observed.

Magnetoelectric Coupling in Metglas/BaTiO<sub>3</sub>/Metglas Lead-Free Magnetoelectric Composites

We report the magnetoelectric (ME) coupling in ME composites composed of NiFe2O4 (NFO) or metglas as magnetostrictive phases and BaTiO3 (BTO) as piezoelectric phase, targeting lead free magetnic field sensors. NFO and BTO phases were synthesized by solid state sintering method and further characterized by using XRD and FESEM techniques. The P-E hysteresis curve shows good ferroelectric behavior with saturation polarization of Ps = 15.87 C/cm2 and coercive electric field of 130 kV/cm. The ME response was characterized as a function of dc magnetic field at a fixed frequency. The transverse ME voltage coefficient, αME31 shows 2 times larger magnitude than that of longitudinal ME voltage coefficient, αME31. The maximum αME31 of 37 mV/cm•Oe (@Hdc = 250 Oe) is observed for NFO/BTO/NFO ME composites with thickness ratio of tm/tp = 1.0. The ME coupling is further enhanced by replacing NFO layers by highly magnetostrictive metglas layers. Metglas/BTO/metglas laminates show large αME31 value of 81 mV/cm•Oe at relatively lower Hdc of 145 Oe. The present laminates can offer promising opportunities of engineering environmental friendly ME laminate for applications in ME devices such as energy harvester and magnetic field sensors.

Study of samarium modified lead zirconate titanate and nickel zinc ferrite composite system

In the present work, composites of samarium substituted lead zirconate titanate and nickel zinc ferrite with compositional formula 0.95Pb 1−3 x /2 Sm x Zr 0.65 Ti 0.35 O 3 –0.05Ni 0.8 Zn 0.2 Fe 2 O 4 ( x =0, 0.01, 0.02 and 0.03) were prepared by the conventional solid state route. X-ray diffraction analysis was carried out to confirm the coexistence of individual phases. Microstructural study was done by using scanning electron microscope . Dielectric constant and loss were studied as a function of temperature and frequency. To study ferroelectric and magnetic properties of the composite samples, corresponding P – E and M – H hysteresis loops were recorded. Change in magnetic properties of electrically poled composite sample ( x =0.02) was studied to confirm the magnetoelectric (ME) coupling. ME coefficient (d E /d H ) of the samples ( x =0 and 0.02) was measured as a function of DC magnetic field. • We are reporting the effect of Sm substitution on PZT–NiZn ferrite composites. • Observation of both P – E and M – H loops confirms ferroelectric and magnetic ordering. • With Sm substitution, significant improvement in properties was observed. • Increase in magnetization for electrically poled sample is evidence of ME coupling. • Electric polarization is generated by applying magnetic field.

Magnetic, magnetoelectric and dielectric behavior of CoFe2O4–Pb(Fe1/2Nb1/2)O3 particulate and layered composites

Magnetic, magnetoelectric and dielectric properties of multiferroic CoFe2O4–Pb(Fe1/2Nb1/2)O3 composites prepared as bulk ceramics were compared with those of tape cast and cofired laminates consisting of alternate ferrite and relaxor layers. X-ray diffraction analysis and Scanning Electron Microscope observations of ceramic samples revealed two-phase composition and fine grained microstructure with uniformly distributed ferrite and relaxor phases. High and broad maxima of dielectric permittivity attributed to dielectric relaxation were found for ceramic samples measured in a temperature range from −55 to 500°C at frequencies 10Hz–2MHz. Magnetic hysteresis, zero-field cooled (ZFC) and field cooled (FC) curves, and dependencies of magnetization on temperature for both magnetoelectric composites were measured with a vibrating sample magnetometer in an applied magnetic field up to 80kOe at 4–400K. The hysteresis loops obtained for composites are typical of a mixture of the hard magnetic material with a significant amount of the paramagnet. The bifurcation of ZFC–FC magnetizations observed for both composites implies spin-glass behavior. Magnetoelectric properties at room temperature were investigated as a function of dc magnetic field (0.3–7.2kOe) and frequency (10Hz–10kHz) of ac magnetic field. Both types of composites exhibit a distinct magnetoelectric effect. Maximum values of magnetoelectric coefficient attained for the layered composites exceed 200mV/(cmOe) and are almost three times higher than those for particulate composites.

Ferroelectric, Magnetic and Magnetoelectric Properties of Ferroelectric Rich Ni0.8Zn0.2Fe2O4-PbZr0.65Ti0.35O3 ME Composites

Magnetostrictive-piezoelectric (magnetoelectric) composites using magnetostrictive nickel zinc ferrite (NZF) and piezoelectric lead zirconate titanate (PZT) having compositional formula yNi0.8Zn0.2Fe2O4-(1-y)PbZr0.65Ti0.35O3 (0 ≤ y ≤ 0.15 in the steps of 0.05) were synthesized by conventional solid state method. Room temperature P-E and M-H hysteresis loops were recorded to study ferroelectric and magnetic properties of composites respectively. Effect of electric poling on values of remanant magnetization (Mr) and saturation magnetization (Ms) was studied for all composite samples (y = 0.05, 0.10 and 0.15) to confirm magnetoelectric (ME) coupling. ME coefficient (dE/dH) was measured as a function of dc magnetic field for all composite samples.

Study of electrical properties and the magnetoelectric effect inNi0.2Co0.8Fe2O4 + PbZr0.8Ti0.2O3 particulate composites

The electric properties and magnetoelectric effect in magnetoelectric (ME) composites with composition(x)Ni0.2Co0.8Fe2O4 + (1 − x)PbZr0.8Ti0.2O3 (PZT—lead zirconate titanate) were studied. The presence of single- (x = 0 and 1) andbi-phases (x = 0.15, 0.30 and 0.45) in the composites was confirmed by x-ray diffraction (XRD)measurements. A structural analysis of the composites was carried out by scanning electronmicroscopy (SEM) measurements. Electric resistivity measurement as a function oftemperature shows the semiconducting nature of the samples. The dielectric constant (ε′) and losstangent (tanδ) decrease rapidly at lower frequencies and remain constant at higher frequenciesfor all the samples. An AC conductivity measurement was used to discussthe conduction mechanism in all the samples. The ME voltage coefficient(dE/dH)H measured as a function of DC magnetic field gives the maximum ME output of 778 µV cm−1 Oe−1 for 15% of ferrite in the composites.

Investigation of the magnetic field angle dependence of resistance, irreversibility field, upper critical field and critical current density in DC sputtered Bi-2223 thin film

We measured resistivity and transport critical current density, J c , as a function of DC magnetic field and the angle ( ϕ) between the surface of the film and the magnetic field on ex-situ annealed, c-axis oriented Bi-2223 thin films fabricated by DC sputtering method. Irreversibility field ( μ 0 H irr ) and upper critical field ( μ 0 H c2 ) were determined from the resistivity versus the applied magnetic field graph. It is observed that critical temperature ( T c ), μ 0 H irr, μ 0 H c2 and J c of the films strongly depend on the direction and strength of the field. While T c of the film without magnetic field is observed to be about 102 K, it is found to decrease to 90 K (85 K) for the applied field perpendicular (parallel) to c-axis of the film. Not only were μ 0 H irr (0) and μ 0 H c2 (0) values determined from the μ 0 H irr and μ 0 H c2 versus temperature graphs, respectively, but also penetration depths and coherence lengths were interpreted. Anisotropy of the film was also discussed by means of the change of irreversibility as a function of angle. Moreover at 4.2 K, J c was observed to be 3000 A/cm 2 at zero field; however, it was found to abruptly decrease to 1982 (1 1 2 0) A/cm 2 under low magnetic field at ϕ=0° ( ϕ=90°), which indicates that anisotropic J c behavior of the film is intrinsic. Furthermore, we provided a theoretical analysis of the obtained results in the framework of intrinsic pinning theory of superconductors. Microstructural properties of the produced films were also reinvestigated by X-ray diffractometer (XRD) and scanning electron microscopy (SEM) measurements. XRD patterns indicate that the films are c-axis oriented based on the prominent (0 0 l) peaks. SEM images show needle-like grain structures dominate the surface morphology of the films.

(1-x) [0.5PZT-0.25PNN-0.25PZN]- x [Ni0.9Zn0.1Fe2O4] 세라믹스의 압전/자성 성질 및 자기전기적 효과

Magnetoelectric composites with compositions (1-x)[0.5PZT-0.25PNN-0.25PZN](ferroelectric) - x[<TEX>$(Ni_{0.9}Zn_{0.1})Fe_2O_4$</TEX>](ferrite) in which x varies as 0, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0 were prepared by conventional ceramic process. The presence of two phases (ferroelectric phase with large grain and ferrite phase with small grain) in the particulate ceramic composites was confirmed by XRD, SEM and EDX. The ferroelectric and magnetic properties of the composites were studied by measuring the P-E and M-H hysterisis loop on the composite composition (x=0, 0.1, 0.2, 1), they were strongly affects of the phase content in composite. The magnetoelectric votage was measured as a function of DC magnetic field and the maximum magnetoelectric voltage coefficient of 14 mV/cm Oe was observed in x=0.2(80 mol% ferroelectric and 20 mol% ferrite phase).

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.

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.

Magnetoelectric properties of Ni/PZT/Ni layered composite for low field applications

A composite material when placed under the external magnetic/electric fields exhibits voltage/induced magnetization is known as magnetoelectric (ME) composite. Such composite materials should have ferroelectric and ferro/ferri magnetic phases as constituents. The magnetoelectric output is exhibited as a product property. Magnetoelectric composites are being used for variety of applications including resonators, filters, phase shifters, optical isolators, actuators and magnetic field sensors. Metal/ferroelectric/metal magnetoelectric composite using Ni and PZT as constituent phases has been fabricated in 2-2 composite pattern to study its product property. The paper presents magnetoelectric studies of Ni/PZT/Ni composite using low dc magnetic field magnetoelectric set-up. Using this ME set-up ME output of Ni/PZT/Ni composite is studied as a function of dc magnetic field. The results were analyzed to identify the useful magnetic field (dc and ac) range in which Ni/PZT/Ni sensor can be utilized for applications.

Magnetic properties and magnetoelectric (ME) effect in ferroelectric rich Ni 0.2Co 0.8 Fe 2O 4 + PbZr 0.8Ti 0.2O 3 ME composites

Magnetoelectric composites with composition ( x) Ni 0.2Co 0.8Fe 2O 4 (ferrite) + (1 − x)PbZr 0.8Ti 0.2O 3 (ferroelectric) in which x varies as 0.0, 0.15, 0.30, 0.45 and 1.0 mol% have been prepared by double sintering ceramic method. The X-ray diffraction pattern of the composites reveals the formation of spinel structure for the ferrite phase and perovskite structure for the ferroelectric phase without any other phase formation. Scanning electron micrographs (SEM) were taken to understand the microstructure and grain size of the samples. The estimated values of the porosity of the samples lie between 4.5% and 16.2%. Hysteresis measurements were used to determine saturation magnetization ( M s) and magnetic moment ( μ) and the variations of saturation magnetization and magnetic moment were interpreted in terms of the composition of the samples. From AC susceptibility studies the contribution of both single domain (SD) particle of the ferrite phase and mixed (MD + SD) particle of the composites in ME output was discussed. The magnetoelectric voltage coefficient (d E/d H) H was measured as a function of DC magnetic field and the maximum value of ME conversion factor was observed (828 μV cm −1 Oe −1) for the composite with 15% ferrite and 85% ferroelectric phase.

Experimental Presentation of Microwave Absorption due to Shaking of JV by AC Magnetic Field in Bi2212 and Bi2223

The Josephson Vortex dynamics in high anisotropy superconductors Bi2212 and Bi2223 induced by AC magnetic field collinear to DC magnetic field and parallel to the layers is studied via their interaction with microwave field. Experimental results as function of DC magnetic field, AC magnetic field and temperature are presented. The AC induced microwave dissipation is larger than dissipation without AC field. The results are explained by the theoretical interpretation reported recently due to shaking by the AC field that depins the JV (Shaltiel et al., Phys. Rev. B 77, 014508, 2008). Similar behavior in these two compounds as a function of the variables involved discloses that the shaking effect should be observed in any high anisotropy superconductors. It shows that the AC field interacting with JV has an active and not the usual passive modulating role of the DC field in EPR dissipation experiments. The technique can be used to investigate JV dynamics and JV phase diagram.

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.

Giant magnetoimpedance in amorphous (Co 0.93Fe 0.7) 63Ni 10Si 11B 16 glass-coated microwire

Giant magnetoimpedance (GMI) effect has been measured in a glass-coated amorphous (Co 0.93Fe 0.7) 63Ni 10Si 11B 16 microwire as a function of DC magnetic field and up to the frequency of 11 MHz. The sample shows single peak GMI characteristics within the whole range of frequency. The domain structure of the above sample has been changed by applying tensile stresses up to 603 MPa and current annealing with a DC current of 50 mA for various time durations, and the corresponding effect on GMI has been studied in detail. A maximum change of 8.85% in MI of the as-quenched sample has been observed around a frequency of 5.05 MHz. Application of an external tensile stress reduces the GMI value by increasing the inner core domain, whereas heat treatment of the sample enhances the same. The square-shaped magnetic hysteresis loop of the as-quenched sample helps us understanding the MI results.