Multiferroic Composites Research Articles

A study on BaTiO3 – NiFe2O4 composite; microstructure, multiferroic and magnetodielectric properties

The lead-free x NiFe2O4 – (1-x) BaTiO3 (x = 0, 0.05, 0.1, 0.15) multiferroic composites were prepared via the solid-state sintering technique. Microstructure, multiferroic, and magnetodielectric properties of composites were investigated. According to the XRD data (from x = 5 to 15 wt%), the tetragonality factor (cT/aT) and unit cell volume of the BaTiO3 (BTO) crystal system diminished. Based on SEM images, ferromagnetic NiFe2O4 (NFO) grains are uniformly dispersed in the ferroelectric BTO matrix without additional reaction in the interfaces of two phases. The highest values of dielectric (dielectric constant (εr) ∼ 1905 and dielectric loss factor (tan δ) ∼ 0.049) and ferroelectric properties (saturation polarization (PS) ∼ 13 μC/cm2 and remnant polarization (Pr) ∼ 10 μC/cm2) are attained for x = 5 wt% due to the lowest NFO (non-ferroelectric) concentration. Also, with increasing ferrite concentration (up to 15 wt%), the ferroelectric properties of the composites show a gradual decrease. The saturation magnetization (MS) values rise due to increasing ferrite concentration (from 2 to 5 emu/g for x = 5 to 15 wt%). Moreover, coercivity (HC) drops from 150 to 110 Oe. The simultaneous observation of the ferroelectric and ferromagnetic characteristic hysteresis loops confirmed the multiferroic effect for x = 5, 10, and 15 wt%. The highest magnetodielectric constant (3 %) is obtained for x = 15 wt% multiferroic composite at the applied magnetic field of 6 kOe.

Role of Pb(Zr0.52Ti0.48)O3 on Electric, Dielectric, Electromagnetic Wave Absorption Characteristics of Multiferroic Nanocomposites for Magnetoelectric Devices

Multiferroic composites of ferrite and ferroelcectric phases with systematically varying concentration (100-x)Mg0.48Cu0.12Zn0.4Fe2O4 + x Pb(Zr0.52Ti0.48)O3 (MCZPZT) ( where, x mol% = 0, 20, 40, 50, 60, 80, 100) were prepared by mechanical alloying and sintering methods. The dc resistivity and dielectric constant of the samples as a function of temperature were studied in detail and obtained results are reported. The magnetoelectric effect was investigated for the composites. The sample with 80% ferroelectric phase (MP5), shows largest magnetoelectric output voltage coefficient (dE/dH) H value of 880 μVcm.Oe at 2000 Oe magnetic field. Electromagnetic interference shielding properties of transmission loss and attenuation constant were determined for the composites. Skin depth decreases with frequency from 0.29 to 0.2 cm in the range 8–12 GHz for all composites. The composite MP5 with 80% PZT shows lowest α value between 282 dB m−1 and 414 dB m−1 throughout X-band frequencies. The present results proved that the current magnetoelectric materials of all concentrations exhibit strong magnetoelectric coupling with excellent microwave absorbing performance in X-band region and are appropriate for EMI shielding and novel device applications.

Enhancement of Microwave Absorption Properties of Crystal‐Engineered Perovskite Oxide Using Cobalt Ferrite

A multiferroic composite that comprises of a non‐ferromagnetic ferroelectric material with a high dielectric constant and a non‐ferroelectric ferromagnetic material with a high magnetostriction is of tremendous interest as microwave absorption material due to its applicability in tunable microwave phase shifters, resonators, filters, absorbers, etc. In the previous work, the solid solution of strontium titanate and sodium bismuth titanate (Sr0.5(Na0.5Bi0.5)0.5TiO3, SNBT50), which is observed to possess a very high dielectric constant at room temperature (Ferroelectrics, Vol 583, 252–263 [2021]), is successfully reported. Thus, in this work, a core–shell magnetoelectric composite is prepared by coating highly ferromagnetic and magnetostrictive cobalt ferrite onto a diamagnetic but strongly ferroelectric SNBT50 to enhance its magnetic properties and to investigate the modification in microwave absorption. Detailed characterization of electric and magnetic parameters in microwave frequency range (1–20 GHz) reports substantial enhancement in the magnetic permeabilities as well as the magnetic loss of the composite system, as opposed to bare SNBT50. This results in improved impedance matching in the system and enhanced microwave absorption, with a minimum reflection loss (RL) of −20.19 dB and an increased effective absorption bandwidth of 4.56 GHz at a mere 2.7 mm absorber length. Consequently, in this investigation, a promising pathway is established for the development of multiferroic composites with favorable magnetoelectric coupling at room temperature that possesses wide absorption bandwidth and suitable RL, making them highly suitable for use in multiferroic‐based microwave components.

Magnetic and dielectric properties of the new YFeO3/BiFeO3 nanocomposite ceramics prepared via reverse chemical co-precipitation followed by spark plasma sintering

New xYFeO3 – (1-x) BiFeO3 (0.0 ≤ x ≤ 1.0) multiferroic composites were prepared successfully via the chemical co-precipitation followed by high energy mechanical blending. For the structural analysis, assessment of phase purity, and characterization of oxidation states, XRD, FTIR and XPS methods were utilized, respectively. Furthermore, morphological investigations and elemental distribution within the composite samples were elucidated through FESEM and TEM imaging techniques. The VSM results indicated that the values of Ms and Mr increase alternately from 0.553emu/g and 0.049emu/g to 1.210emu/g and 0.166emu/g, respectively, with an increase in the YFO content from 20 % to 80 %. These values of Ms do not follow a linear combination of the base phases, and the magnetization of each composite sample is accompanied by an additional value. This additional value may arise from the residual strain and interfacial magnetic and electrical interactions between the parent phases. The measurements of dielectric properties disclosed that the behavior of the samples follows the Maxwell-Wagner polarization. Moreover, the values of ε′ at the frequency of 200 Hz increased from 149 to 303 as the BFO content rose from 20 % to 80 %. In addition, the lowest recorded tanδ value was 0.56 for the 6Y4B sample at 200 Hz. Furthermore, the conductivity measurements showed that the behavior of all samples follows Johnscher's power law.

An energy efficient way for quantitative magnetization switching

Recent advancements in electrically controlled spin devices have been made possible through the use of multiferroic systems comprising ferroelectric (FE) and ferromagnetic (FM) materials. This progress provides a promising avenue for developing energy-efficient devices that allow for electrically controlled magnetization switching. In this study, we fabricated spin orbit torque (SOT) devices using multiferroic composites and examined the angular dependence of SOT effects on localized in-plane strain induced by an out-of-plane electric field applied to the piezoelectric substrate. The induced strain precisely modulates magnetization switching via the SOT effect in multiferroic heterostructures, which also exhibit remarkable capability to modulate strain along different orientations – a feature with great potential for future applications in logic device arrays. To investigate the influence of electric fields on magnetization switching, harmonic Hall measurements, synchrotron-powered x-ray magnetic circular dichroism-photoemission electron microscopy (XMCD-PEEM), x-ray diffraction (XRD), magnetic force microscopy (MFM), and micromagnetic simulation were conducted. The results demonstrate that electric-field-induced strain enables precise control of SOT-induced magnetization switching with significantly reduced energy consumption, making it highly suitable for next-generation spin logic devices.

Investigation of magneto-electric properties of Co0.65Zn0.35Fe2O4–Ba0.7Sr0.3TiO3 multiferroic composites

Investigation of magneto-electric properties of Co0.65Zn0.35Fe2O4–Ba0.7Sr0.3TiO3 multiferroic composites

Strong magnetoelectric coupling in novel Na0.5Bi0.5TiO3–BaFe12-2xCoxTixO19 multiferroic composite

Multiferroic composites of sol-gel synthesized Sodium Bismuth Titanate (Na0.5Bi0.5TiO3) and Co–Ti substituted Barium Hexaferrite (BaFe12-2xCoxTixO19; x = 0.0, 0.5, 1.0, 1.5 and 2.0) in the ratio 3:1 was synthesized through ceramic route. Successful formation of R3c rhombohedral and P63/mmc hexagonal phases corresponding to Na0.5Bi0.5TiO3 and BaFe12-2xCoxTixO19 respectively was confirmed from the XRD and Rietveld refinement pattern. The frequency and temperature dependence of dielectric constant and loss of the composite systems exhibited typical dispersion behaviour which could be understood using the Maxwell-Wagner model. Substituted samples showed enhanced dielectric behaviour where dielectric constant was observed to increase while loss tangent decreased. Using the Universal Jonscher's Power law (JPL), conductivition mechanisms of the composite systems were studied from the ac conductivity behaviour which revealed that the x = 0.0 sample followed Non-overlapping Small Polaron Tunnelling (NSPT) model while the remaining samples followed the Correlated Barrier Hopping (CBH) model. The complex impedance and Nyquist plot analysis showed the enhancement of resistive property in the x≠0 systems. Magnetic hysteresis loop measurements were conducted, and the associated parameters were determined with the assistance of the Law of Approach to Saturation (LAS). Favourable reduction in the magnetic anisotropy was observed indicating the disturbance of magnetic spin structure in the hexaferrite phase. The P-E loops established the novel room temperature multiferroic nature of the composite systems. Significant magnetoelectric coupling was detected at room temperature in all samples, with the x = 0.5 sample exhibiting the highest value of approximately 59.81 mV/cmOe. These desirable properties suggest that the composites may find future device applications as in magnetically tunable energy harvesting devices and self-powered magnetoelectric sensors in the future.

Impacts of diffusive ion migration on ferroelectric properties in BaTiO3 composite

Multiferroic composites, combining ferroelectric and ferromagnetic properties, hold significant promise in today’s technology landscape in a diverse array of fields including information storage devices, energy harvesters, current and magnetic field sensors, tunable devices, and various other domains. Exploring the interaction between these materials and their impact on multiferroic properties is crucial for advancing miniaturized, high-performance devices. A deeper understanding of the interplay between ionic dynamics and microstructure is essential for engineering these composites effectively. This study examines the deterioration of the ferroelectric property of BaTiO3 composite with the incorporation of the magnetic BaFe12O19. The composite is synthesized using the conventional solid-state reaction method. Structural analysis involves x-ray diffraction, Raman spectroscopy, and field-emission scanning electron microscopy. The dielectric and ferroelectric investigations, as well as magnetic analysis, are conducted. The study shows the existence of the electron hopping between different oxidation states of the cations and it elevates the material’s conductivity and, generates a leakage current that largely affects the ferroelectric properties by preventing saturation polarization.

Study on the magnetoelectric effect, ferroelectric and optical investigation of (1−x) BCT + x NZLFO multiferroic composite

AbstractThis study investigates the magnetoelectric coupling effect in dual‐phase multiferroic composites prepared using a solid‐state reaction method. The composites were fabricated with the formula (1−x)Ba₀.₇₇Ca₀.₂₃TiO₃(BCT) + xNi₀.₆Zn₀.₂₅La₀.₁₅Fe₂O₄(NZLFO), where x varied from 0% to 100% in 10% increments. Ca‐doped BaTiO₃ served as the ferroelectric phase, while La‐doped Ni–Zn ferrite acted as the ferromagnetic phase. The effects of varying ferrite content (x) on structural, optical, ferroelectric, electrical, and magnetoelectric properties were comprehensively analyzed. X‐ray diffraction (XRD) with Rietveld refinement revealed a spinel cubic structure for the ferrite phases and a tetragonal structure for the perovskite phases. The study observed a moderate influence of ferrite concentration on the lattice parameters of BCT and an opposing effect on the lattice parameters of NZLFO. Optical measurements indicated higher light absorption in the visible range compared to the UV region and wide optical bandgap. Magnetic properties, characterized by saturation magnetization, exhibited a dependence on temperature, with a Curie temperature (Tc) of 700 K. Electrical resistivity displayed a maximum at x = 50% and remained constant at high frequencies. The study also confirmed the presence of electric polarization induced by a magnetic field, with the highest magnetoelectric coefficient observed at x = 10%. These findings demonstrate the successful fabrication of dual‐phase multiferroic composites with tunable properties through controlled ferrite content. The observed magnetoelectric coupling suggests potential applications in multifunctional devices.

Phase-field simulation and machine learning of low-field magneto-elastocaloric effect in a multiferroic composite

Achieving appreciable elastocaloric effect under low external field is critical for solid-state cooling technology. Here, a non-isothermal Phase-Field Model (PFM) coupling martensitic transformation with mechanics, heat transfer and magnetostrictive behavior is proposed to simulate Magneto-elastoCaloric Effect (M-eCE) that is induced by magnetic field in a multiferroic composite (e.g., Magnetostrictive-Shape Memory Alloys (MEA-SMA) composite). In the PFM, a nonlinear constitutive hyperbolic tangent model is utilized to model the macroscopic magnetostrictive behavior of MEA, and the heat transfer coupled with phase transformation is employed to calculate the adiabatic temperature change (ΔTad) during M-eC cooling cycles. The influences of magnetic field, geometrical dimension, and ambient temperature on ΔTad are comprehensively investigated. Machine Learning (ML) is further conducted on the database from PFM simulations to accelerate the prediction and design of MEA-SMA composite with an improved ΔTad. It is found that a large ΔTad of 10–14 K and a wide working temperature window of 30 K can be achieved under ultra-low magnetic field of 0.15–0.38 T by optimizing the composite’s geometrical dimension. The present work combining PFM and ML for evaluating M-eCE provides a theoretical framework for the optimization of M-eC cooling devices, and is also potentially extended to other multicaloric effects (e.g., electro-elastocaloric effect).

Magnetoelectric Properties of Multiferroic Composites Based on BaTiO3 and Nickel-Zinc Ferrite Material.

The purpose of the present study was to learn the morphological, structural, ferroelectric, dielectric, electromechanical, magnetoelectric, and magnetic properties, and DC conductivity of BaTiO3-Ni0.64Zn0.36Fe2O4 (BT-F) multiferroic composites compacted via the free sintering method. The influence of the ferrite content in ceramic composite materials on the functional properties is investigated and discussed. X-ray diffraction studies confirmed the presence of two main phases of the composite, with strong reflections originating from BaTiO3 and weak peaks originating from nickel-zinc ferrite. BT-F ceramic composites have been shown to exhibit multiferroism at room temperature. All studied compositions have high permittivity values and low dielectric loss, while the ferroelectric properties of the BT component are maintained at a high level. On the other hand, magnetic properties depend on the amount of the ferrite phase and are the strongest for the composition with 15 wt.% of F (magnetization at RT is 4.12 emu/g). The magnetoelectric coupling between BT and F phases confirmed by the lock-in technique is the largest for 15 wt.% ferrite. In the present work, the process conditions of the free sintering method for obtaining BT-F multiferroic composite with good electrical and magnetic properties (in one material) were optimized. An improved set of multifunctional properties allows the expansion of the possibilities of using multiferroic composites in microelectronics.

Optimizing energy storage and magnetoelectric performance through core–shell engineering: A study on Ni0.5Co0.5Fe2O4-BaTiO3 multiferroic composite materials

In this report, we have synthesized Ni0.5Co0.5Fe2O4 (NCFO) and BaTiO3 (BTO) core–shell (12 % NCFO − 88 %BTO) multiferroic nanopowder by hydrothermal method and sol–gel method, respectively. The structural, morphological, ferroelectric, and magnetoelectric properties of the as- prepared sample was investigated in detail. X-ray diffraction results revealed that no secondary phase is obtained. As investigated from the scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis, the grains are almost spherical, which depicts the core–shell like morphology and the presence of all the constituent elements in the prepared sample. FTIR analysis gives information about the formation of two individual phases and the different chemical compositions present in the sample. The prepared core–shell composite exhibits a notable energy storage density W (38.25 mJ/cm3), accompanied by a slightly lower energy storage efficiency η (46.50 %) and energy loss density Wrec (17.78 mJ/cm3). Magnetic characterization revealed that the sample shows lower saturation magnetization (1.33 emu/g) with coercivity (430 Oe) and magneto-crystalline anisotropy (595.7 erg/g). A moderate magnetoelectric coefficient of 18.34 mV/cm*Oe is observed on the higher field side, surpassing the value on the lower field side 32.62 mV/cm*Oe. Anisotropy in the system leads to varying magnetoelectric coefficients in different directions. These findings provide valuable insights for enhancing the magnetoelectric response in core–shell multiferroic composites.

Fe-enriched two-phase multiferroic composites based on lead ferroniobate - titanate and modified nickel ferrite

Iron-enriched ferroelectrics are of particular interest as piezoactive components of piezoelectric-ferrite ME ceramics. This is due to the phase composition similarity and the reduction of expected interfacial doping effects during high-temperature calcination. This idea seems attractive, but laborious due to the significantly limited number of possible piezoelectric–ferrite combinations. Therefore, there is practically no data on such systems in the literature. ME composite ceramics based on the highly efficient Fe-containing Pb(Fe0.5Nb0.5)0.935Ti0.065O3 (PFNPT) ferroelectric has been studied. (100-х) wt.% Pb(Fe0.5Nb0.5)0.935Ti0.065O3 (PFNPT) + х wt.% Ni0.9Co0.1Cu0.1Fe1.9O4-d (NCCF) composite systems has been obtained by the solid-state method at 1050 °C, with no foreign phases. The specimens densities amounted to ∼80% of the theoretical. It has been shown that the ME conversion efficiency and other composites properties are significantly influenced by the PFNPT precursor pre-treatment method. The maximum value of the ME coefficient ΔΕ/ΔΗ = 75 mV/(cm Oe) has been observed for specimens with x = 50–60 made from PFNPT powder with the addition of Li2CO3. An increase in the ME composites sintering temperature to 1150 °C leads to the formation of Pb2Nb2O7 foreign phase with a pyrochlore structure along the grain boundaries. The ME coefficient ΔΕ/ΔΗ does not exceed 15 mV/(cm⋅Oe). There is an threefold decrease in the composites piezoelectric parameters (piezoelectric coefficients dij, gij), as well as in their magnetic properties (magnetizations MS, MR) due to piezophase degradation, which is presumably associated with a change in the cations distribution over A and B sublattices of the spinel structure.

Probing of structural, electrical, and dielectric properties of samarium doped composite of barium titanate (Ba0.5Sm0.5TiO3) and cobalt ferrite (Co0.5Sm0.5Fe2O4)

Multiferroic composites exhibit remarkable magnetoelectric (ME) characteristics, offering diverse applications. The study investigated samarium (Sm) doped composites, specifically (1 − x)Ba0.5Sm0.5TiO3–xCo0.5Sm0.5Fe2O4 (x = 0.0,0.02,0.04,0.06), formed by combining Sm doped BaTiO3 and CoFe2O4 using the solid-state reaction method. X-ray diffraction analysis revealed a tetragonal structure in Ba0.5Sm0.5TiO3 (SmBT) and a cubic spinel secondary phase in Co0.5Sm0.5Fe2O4 (SmCF), suggesting uniform distribution of grains. The optical bandgap in SmBT and the composite showed a slight decrease (from 3.14 eV to 3.01 eV) with increasing Sm concentration, as observed in optical studies. The dielectric measurements showed that the dielectric constant of SmBT was higher (ϵ′ = 526.3) between 80 Hz and 8 MHz, while the composites had a lower dielectric constant (ϵ′ = 438.4) at lower frequencies and the real part of dielectric was fitted by Havriliak–Negami (H–N) model shows that the dielectric curves exhibit a characteristic dispersion pattern known as the cole–cole mode (grains) also confirmed by cole–cole plot. The response exhibited linearity, adhering to the universal dielectric response model. Ferroelectric behaviour in the underlying material confirms SmBT non-centrosymmetric character and the storage efficiency (η) of all composites surpassed 90%, reaching a peak of 94.8% with a ferrite content of 0.02. The versatility of the Sm-doped composites offers opportunities for diverse applications in fields such as electronics, telecommunications, and biomedical devices. Notably, these materials can be utilized in Memory Devices, Actuators, and other relevant applications.

Exploring the magnetic, electric and magnetodielectric properties of (1 − x)Ba0.9Ni0.1Ti0.9Mn0.1O3–xCo0.9Mn0.1Fe1.9V0.1O4 multiferroic composites

In this study, 0–3 particulate multiferroic composites were synthesized using the solid-state reaction method.

Investigation of BaTiO3/ Cu1-xMgxFe2O4 nano-multiferroic composites

In the present work, the citrate precursor approach has been used to generate nano-particle ferrites with the chemical composition Cu1-xMgxFe2O4 (where x = 0.0, 0.5, and 1). Multiferroic composites of BaTiO3 along with the three samples of Cu-Mg ferrites have been prepared using two percentages of BaTiO3 (30 % and 70 %) with each one of the three ferrites. X-ray fluorescence (XRF) and X-ray diffraction (XRD) have been used to characterize the samples under investigation, indicating that the intended samples have formed without impurities. The average particle size of the samples has been estimated from the XRD patterns (64.1 nm for BaTiO3, 85.8 nm for CuFe2O4, 83.5 nm for Cu0.5Mg0.5Fe2O4 and 89.2 nm for MgFe2O4) and have been fairly verified using a transmission electron microscope (TEM) too. A vibrating sample magnetometer (VSM) has been used to study the magnetic characteristics; where the maximum saturation magnetization is recorded for the Mg ferrite as 26.549 emu/g and the maximum coercive field is found for the Cu ferrite as 1085.13G. A variation of the examined samples from hard to soft ferrite has been noticed by introducing Mg such that we can conclude that the Cu0.5Mg0.5Fe2O4 and MgFe2O4 samples may be suitable for high-frequency devices. The decrease in magnetic properties with introducing BaTiO3 has been recorded too. The ferroelectric properties have been investigated and the results show a ferroelectric behavior of BaTiO3 that reveals its nanostructure. An enhancement of conduction current has been recorded by the addition of CuFe2O4, MgFe2O4, and Cu0.5Mg0.5Fe2O4. The maximum values of conduction current have been achieved the pure Mg ferrite and at the samples containing 70 % ferrites in the composite samples in agreement with literature. Finally, it is worth mentioning that the samples exhibiting lossy capacitor behavior may be used as piezoelectric actuators.

Magnetoelectric behaviour of Pb-free Na0.5Bi0.5TiO3-Ni0.5Co0.5Fe2O4 particulate novel ceramic composites

Magnetoelectric (ME) multiferroic composites are more promising candidates for low-power consumption devices, next-generation spintronic devices, and multistate memory devices since they exhibit significantly higher Magnetoelectric interaction over single-phase multiferroics. In this regard magnetic behaviour, dielectric, and magnetoelectric characteristics of a novel Pb-free (1-x) Na0.5Bi0.5TiO3-(x) Ni0.5Co0.5Fe2O4, (x = 0, 0.2, 0.4, 0.6, 0.8 & 1) particulate composites were explored. Solid-state synthesis was adopted to prepare the single-phase Na0.5Bi0.5TiO3 (NBT), Ni0.5Co0.5Fe2O4 (NCFO), and their composites. The presence of rhombohedral NBT and cubic inverse spinel NCFO in the composites were confirmed with X-ray diffraction (XRD) patterns. Microstrain (ε) induced in the prepared samples was estimated by using the Williamson-Hall (W-H) method. The piezoelectric NBT phase shows the tensile strain and the ferromagnetic NCFO shows the comprehensive strain. Among all the composites 0.8NBT-0.2NCFO shows a higher strain value of 0.012%, and the decrement in the strain values was observed upon increases in ferrite concentration. Backscattered scanning electron microscope (BS-SEM) images revealed the existence of highly dense uniformly distributed elements and Energy dispersive spectroscopy (EDS) confirmed the existing elements in the composites. UV–vis absorbance spectra disclosed a rise in energy gap values from 1.14 eV to 3.0 eV with increasing NBT percentage. Variations of dielectric permittivity and dielectric loss with respect to AC frequency were studied at room temperature (RT), and the 0.2NBT-0.8NCFO sample shows a high dielectric permittivity of 8500 at ∼100Hz. M − H (Magnetization-Magnetic field) hysteresis loops demonstrate the pure ferrite phase has a coercive field (Hc) = 578 Oe, remnant magnetization (Mr) = 21.43 emu/g and saturation magnetization (Ms) = 71.29 emu/g. The Ms and Mr values in the composites are enhanced with increasing ferrite percentage. Studies on ME behaviour of (1-x) NBT-(x) NCFO, (x = 0.2,0.4,0.6 & 0.8) show the coupling effect between both the phases at room temperature and the highest coupling coefficient value 3.16mV/Cm. Oe was observed for the 0.8NBT-0.2NCFO further the reasons and mechanisms are discussed.

Electrophysical Properties of the Three-Component Multiferroic Ceramic Composites.

Using the free (pressureless) sintering method, multiferroic ceramic composites based on two ferroelectric materials, i.e., BaTiO3 (B) and Pb0.94Sr0.06 (Zr0.46Ti0.54)0.99Cr0.01O3 (P), and magnetic material, i.e., zinc-nickel ferrite (F) were obtained. Three composite compositions (BP-F) were obtained with a constant 90/10 content (ferroelectric/magnetic) and a variable content of the ferroelectric component (B/P), i.e., 70/30, 50/50, and 30/70. Crystalline structure, microstructural, DC electrical conductivity, dielectric, and ferroelectric properties of multiferroic composites were investigated. The concept of a composite consisting of two ferroelectric components ensures the preservation of sufficiently high ferroelectric properties of multiferroic composites sintered by the free sintering method. Research has shown that the percentage of individual ferroelectric components in the composite significantly affects the functional properties and the entire set of physical parameters of the multiferroic BP-F composite. In the case of the dielectric parameters, the best results were obtained for the composition with a more significant amount of BaTiO3; i.e., permittivity is 1265, spontaneous polarization is 7.90 µC/cm2, and remnant polarization is 5.40 µC/cm2. However, the most advantageous set of performance parameters shows the composite composition of 50BP-F.

Structural analysis, ferroic properties with enhanced magnetoelectric coupling in novel (1-x)BiFeO3-(x)GdFeO3 nanocomposites

Multiferroic composites exhibit substantially greater magnetoelectric interaction among order variables as compared to single-phase multiferroics, making them particularly attractive for futuristic multi-state RAM and spintronic gadgets. The multiferroic nanocomposites (1-x)BiFeO3-xGdFeO3 (x = 0.05, 0.10, 0.15, & 0.20) are synthesized by using solid-state route. The crystallographic and profile parameters are extracted from the dual-phase refinement of the rhombohedral (R3c) and orthorhombic (Pbnm) crystal structures. The optimized density, crystallite size and homogenous microstructure may be responsible for the improved dielectric and ferroic properties. TEM images reveal a reduction in the particle size (67–59 nm) upon GdFeO3 (GFO) loading. The HRTEM images unravel the interplanar spacing and associated Bragg planes, while the SAED rings validate the polycrystalline features of the samples. The high Curie temperature (Tc ̴ 643 °C) with enhanced specific heat (Cp ̴ 29.5 J/g°C) in x= 0.10 sample ensures its stable operation, efficient heat dissipation, minimal overheating, and greater thermal stability for reliable performance in demanding conditions. The surface and finite-size effects enhanced the magnetization (MS=1.04emu/g) in nanostructured ferromagnetic nanocomposite, making it a promising candidate for high-density magnetic storage devices and sensors. The high polarization (Pmax=8.39µC/cm2) and ME-coupling coefficient (αE=0.16mVcm−1Oe−1) observed in the most dense nanocomposite make it a potential candidate for magnetoelectric applications.

Multiferroic and magnetic characterization of nickel ferrite- barium titanate nanocomposites

Nickel ferrite (NiFe2O4) samples were prepared by the modified sol–gel technique which is an effective, simple, and rapid synthesis method. Multiferroic composites of nickel ferrite and barium titanate (NiFe2O4-BaTiO3) in the ratio 1:1, 1:2, 2:1 as well as composites of nickel zinc ferrite and barium titanate (Ni1-xZnxFe2O4-BaTiO3) in the ratio 2:1 were synthesized by solid-state reaction method. The formation of nickel ferrite and barium titanate heterogeneous composites was identified using X-ray diffraction analysis (XRD). Magnetic properties were studied using vibrating sample magnetometer at 300 K. The coexistence of ferroelectric and ferromagnetic order confirmed through Magneto-electric (ME) coupling measurement.