Search

Magnetoelectric coupling in some special materials among the multiferroics family can provide an extra degree of freedom for the functioning of future multifunctional devices. In this context, here, we report a systematic study of multiferroic, 3-phase, (1−x)[0.7BiFeO3–0.3CoFe2O4]–xPbTiO3 composites (x = 0, 0.1, 0.2, 0.3, 0.4, and 0.5) with magnetically tunned robust magnetoelectric (ME) coupling. These composites were synthesized through sol–gel technique and sintering process. The crystalline phases of rhombohedral BiFeO3, spinel cubic CoFe2O4, and tetragonal PbTiO3 were confirmed by X-ray diffraction analysis. A scanning electron microscope was used to analyze the surface microstructures and an energy-dispersive spectroscopy provided the stoichiometric elemental confirmation. Significantly improved dielectric, magnetic, ferroelectric, and lower ac-leakage behavior were observed. The optimum best dielectric properties, saturation polarization, saturation magnetization, and ME couplings were observed for the 10% PTO (x = 0.1) in the composite series. These properties confirmed that a critical amount of PTO could provide enhanced, magnetically robust polarization, making it an excellent tuning candidate for composite properties and multifunctional devices. [ABSTRACT FROM AUTHOR]

The structural transformation, ferro-paraelectric and magnetic ordering induced dielectric phase transitions, multiferroic properties, relaxation and conduction mechanisms of (Gd 1- x Ba x)(Fe 1- x Ti x)O 3 ceramics with different compositions (x = 0.0–0.4) have systematically been investigated. The chemical route is adopted for material synthesis. Rietveld refinement reveals the structural transformation from orthorhombic to mixed phase (coexistence of orthorhombic and tetragonal phase) for x > 0.2. The analysis of the FESEM micrographs suggests a decrease in average grain size with the increase in BT in the composition. Dielectric anomalies are explained based on ferroelectric-paraelectric phase transition of BaTiO 3 , polarization induced by a spin reorientation, and antiferromagnetic ordering of GdFeO 3. The multiferroic properties of all the samples are studied from P-E, M-H, and magneto-electric plots. The improved magnetic properties in compositions x = 0.1–0.3, make them suitable candidates for spintronic devices. The maximum magneto-electric coupling coefficient of 4.77 mV/cm‧Oe in the composition x = 0.3, makes it very much suitable for application in magnetoelectric coupling devices. [ABSTRACT FROM AUTHOR]

Copyright of Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales is the property of Academia Colombiana de Ciencias Exactas, Fisicas y Naturales and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Multiferroic composites are the current research interest due to their multi-functional behavior with promising electrical and magnetic properties compared to single crystallographic phase multiferroic materials. Hence, multiferroic composites of (1−x)Bi0.85La0.15FeO3-(x)NiFe2O4 (x = 0 to 0.50) have been investigated by considering Bi0.85La0.15FeO3 as a ferroelectric phase and NiFe2O4 as a magnetic phase. The crystal structure was examined by analyzing the X-ray diffraction (XRD) patterns. Different crystal structure parameters were obtained from the Rietveld refinement of XRD patterns. An increase in the lattice parameters of both Bi0.85La0.15FeO3 (BLFO) and NiFe2O4 (NFO) phases has been observed with the increase in the percentage of NiFe2O4 in the composites. Absorption peaks in Raman spectra shift toward lower frequencies with the increase in the percentage of NFO in the composite. Variation of lattice parameters and shifting of the Raman modes suggest the lattice strain at the interfaces of BLFO and NFO. Theoretical magnetizations were calculated for all composites by using the sum rule (using the magnetization of individual phases) and compared with experimentally observed magnetization. Interestingly, the experimental values of magnetizations of the composites are more than the theoretically calculated ones. It could be due to the lattice strain, which was observed from the XRD and Raman analysis. [ABSTRACT FROM AUTHOR]

We report temperature dependence of dc magnetization, heat capacity, dielectric, magnetodielectric (MDE) coupling, and pyrocurrent on polycrystalline specimens resulting from a gradual dilution of Tb sublattice by Y in an exotic multiferroic Haldane spin-chain system, Tb2BaNiO5, viz., for the series Tb2−xYxBaNiO5 (x = 0.1, 0.2, 0.5, 1, and 1.5). Among various observations, the ones to be stressed are as follows: (i) The Néel temperature (TN1 = 63 K) and the second magnetic feature occurring at (TN2) 25 K get reduced to lower temperatures with increasing x in a linear fashion, with a concomitant lowering of multiferroicity onset temperature below TN2, scaling essentially with x. This finding emphasizes that local effects due to Tb play a major role on multiferroicity. Clearly, 4f dominates to determine this phenomenon—a rare finding in this field. (ii) The magnitude of the change (Δɛ′) in the dielectric constant surprisingly gets maximized for x = 0.1 with respect to that of the parent compound, attaining a relatively large value of about 22% at 15 K for a field of 100 kOe, thereby revealing that a delicate balance of nonmagnetic doping or defects in favorable cases can enhance MDE coupling. (iii) Nonmonotonic changes in Δɛ′ with a magnetic field, also a changing sign for some compositions, reveal interesting metamagnetodielectric behavior. (iv) The magnetoelectric behavior of x = 1.5 composition is found to be somewhat peculiar with respect to that of other compositions. Thus, this solid solution reveals exotic magneto(di)electric coupling anomalies. [ABSTRACT FROM AUTHOR]

We report temperature dependence of dc magnetization, heat capacity, dielectric, magnetodielectric (MDE) coupling, and pyrocurrent on polycrystalline specimens resulting from a gradual dilution of Tb sublattice by Y in an exotic multiferroic Haldane spin-chain system, Tb2BaNiO5, viz., for the series Tb2−xYxBaNiO5 (x = 0.1, 0.2, 0.5, 1, and 1.5). Among various observations, the ones to be stressed are as follows: (i) The Néel temperature (TN1 = 63 K) and the second magnetic feature occurring at (TN2) 25 K get reduced to lower temperatures with increasing x in a linear fashion, with a concomitant lowering of multiferroicity onset temperature below TN2, scaling essentially with x. This finding emphasizes that local effects due to Tb play a major role on multiferroicity. Clearly, 4f dominates to determine this phenomenon—a rare finding in this field. (ii) The magnitude of the change (Δɛ′) in the dielectric constant surprisingly gets maximized for x = 0.1 with respect to that of the parent compound, attaining a relatively large value of about 22% at 15 K for a field of 100 kOe, thereby revealing that a delicate balance of nonmagnetic doping or defects in favorable cases can enhance MDE coupling. (iii) Nonmonotonic changes in Δɛ′ with a magnetic field, also a changing sign for some compositions, reveal interesting metamagnetodielectric behavior. (iv) The magnetoelectric behavior of x = 1.5 composition is found to be somewhat peculiar with respect to that of other compositions. Thus, this solid solution reveals exotic magneto(di)electric coupling anomalies. [ABSTRACT FROM AUTHOR]

We studied the light-induced effects in BiFeO 3 single crystals as a function of temperature by means of optical spectroscopy. Here, we report the observation of several light-induced absorption features, which are discussed in terms of the photostriction effect and are interpreted in terms of excitons. The temperature dependence of their energy position suggests a possible coupling between the excitons and the lattice vibrations. Moreover, there are hints for anomalies in the temperature evolution of the excitonic features, which might be related to the temperature-induced magnetic phase transitions in BiFeO 3. Our findings suggest a coupling between light-induced excitons and the lattice and spin degrees of freedom, which might be relevant for the observed ultrafast photostriction effect in multiferroic BiFeO 3. [ABSTRACT FROM AUTHOR]

This paper reports on a trilayer Ba0.85Ca0.15Zr0.1Ti0.9O3/La0.67Ca0.33MnO3/Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT/LCMO/BCZT) laminated composite fabricated using plasma-activated sintering. The interfacial structure and the electrical, ferromagnetic, and magnetoelectric properties of the laminated composite are characterized in detail. The laminated composite is found to be highly dense with high-quality interfacial bonding, and its dielectric properties are superior to those of BCZT. The characteristics of the ferroelectric and ferromagnetic properties demonstrate the multiferroic nature of the laminated composite, which exhibits a maximum magnetoelectric coefficient of 1.07 mV/cm Oe. [ABSTRACT FROM AUTHOR]

As the reach points of different phases with complex structural features, a morphotropic phase boundary (MPB) in ferroelectric and ferromagnetic solid solutions can significantly enhance the piezoelectric performance and magnetostrictive response, respectively. Recently, the phase-change functional responses related to the multiferroic MPB are proposed to be a promising way to enhance the magnetoelectric coupling in BiFeO3-based single phase multiferroics. In this work, we verify the tunable magnetic ordering and the construction of the multiferroic MPB by engineering the chemical concentrations of the ferroelectric/non-magnetic PbTiO3 end in the (1 – x)Bi0.9Dy0.1FeO3-xPbTiO3 binary solid solution ceramic system. Based on the results obtained in this work and reported in the literature, the structure-ferroic properties phase diagram of the BiFeO3-DyFeO3-PbTiO3 ternary system is established, where a compositional region with coexisting ferroelectric polarization and ferromagnetic moment is found. More importantly, a multiferroic MPB line separating two chemical regions with distinct crystal structures and ferroic orderings is discovered in the phase diagram. The phase changing nature of MPB compositions with temperature and compositions is investigated from room temperature to high temperature paraelectric phase. This work could provide a promising system to explore the highly desired colossal effects on magnetoelectric coupling in single phase multiferroics by phase-change functional responses. [ABSTRACT FROM AUTHOR]

BiFeO3 (BFO), a room temperature multiferroic, undergoes a series of structural transformations under varying strain conditions by utilizing appropriate substrates for a specific strain condition. In this study, epitaxial thin films of BFO were grown on La0.7Sr0.3MnO3±δ (LSMO), a strain tuning layer on LaAlO3[LAO (001)] substrates, using pulsed laser ablation. LSMO layers of varying thicknesses from 2 nm to 20 nm were grown followed by a BFO layer of a fixed thickness (20 nm). A strained layer of ∼2 nm thick LSMO stabilizes the tetragonal like phase of BFO. Increasing the thickness of the LSMO layer to 10 nm results in a mixed phase with rhombohedral (R) and tetragonal (T) domains, and a further increment of the LSMO layer thickness to 20 nm stabilizes the rhombohedral phase of BFO. The tetragonal phase with weak monoclinic distortion possessed 180° domains with dominant out-of-plane polarization components. However, the mixed phase (R + T) possessed various plausible polarization components in both out-of-plane and in-plane directions. Further, a thermodynamically consistent model based on the phase field approach was implemented to investigate the role of strain on the formation of domain patterns with various polarization components and piezoelectric coefficients. The simulated domain structure exhibited a similar transformation on the dominant polarization components as observed in experiments across different phases of BFO. Our simulations show that the elastic constraint along the z-direction enhances the tetragonality of BFO. The piezoelectric (d33) coefficient was found to be ∼46 pm/V for the 20 nm mixed phase BFO, which was nearly a 200% increment compared to the single phase BFO thin films on LAO. [ABSTRACT FROM AUTHOR]

Coupled ferromagnetic and antiferromagnetic bilayers are an important class of materials that allow manipulating magnetic properties, including the interfacial exchange bias phenomenon. Bismuth ferrite, BiFeO 3 , is the most studied single-phase magnetoelectric multiferroic due to its unique ferroelectric and antiferromagnetic orderings well above room temperature. We report on a systematic experimental study regarding the direct correlation between the Bi 2 O 3 parasitic phase concentration in the BiFeO 3 and the magnetic properties of the polycrystalline heterostructure BiFeO 3 /Ni 81 Fe 19 deposited via magnetron sputtering. It was found that the macroscopic exchange field, that arises from exchange bias coupling, is zero for phase-pure BiFeO 3 and increases up to 18 Oe on increasing the concentration of Bi 2 O 3. This trend is in agreement with the azimuthal behavior of the magnetization reversal. The structural characterization also indicates that phase-pure BiFeO 3 has a disordered mesoporous structure. The influence of the Bi 2 O 3 parasitic phase and mesoporous state, that is known to exist and introduce defects in the polycrystalline bilayers of BiFeO 3 /Ni 81 Fe 19 , on the magnetization reversal and exchange bias coupling is reported for the first time in this study. [ABSTRACT FROM AUTHOR]

BiFeO3 represents the most extensively investigated multiferroic due to its fascinating ferroelectric domain structures, large polarization, and multiferroic coupling, among many other emergent phenomena. Nevertheless, much less concern with the piezoelectricity has been raised while all these well addressed properties are identified in thin film BiFeO3, and bulk ceramic BiFeO3 has never been given priority of attention. In this paper, we report our experiments on the ferroelectric and piezoelectric properties as well as domain structures of BiFeO3 bulk ceramics synthesized by rapid hot-press sintering. It is revealed that these properties are strongly dependent on the microstructural quality, and the largest piezoelectric coefficient d33 = 55 pC/N with electric polarization as large as 45 μC/cm2 is obtained for the sample sintered at 800 °C, while they are only 30 pC/N and 14 μC/cm2 for the samples sintered in normal conditions at 800 °C. The two-level hierarchical stripe-like and irregular dendrite-like domain structures are observed in these hot-press sintered samples. It is suggested that the enhanced piezoelectric property is ascribed to the two-level hierarchical stripe-like domain structure which may respond more easily to electrical and strain stimuli than those irregular dendrite-like domains. The enhanced remnant polarization should be owing to the improved sample quality and large grains in the properly hot-press sintered samples. [ABSTRACT FROM AUTHOR]

The effect of Y and Mn substitution on the structural, magnetic, and dielectric properties of Bi 1 − x Y x Fe 1 − y Mn y O 3 (x = y = 0 ; x = 0.03 , 0.06 , 0.12 , y = 0.05) is investigated. X-ray diffraction and Raman spectroscopy analysis revealed that all the compounds were stabilized in the Rhombohedral structure (Space group: R3c) below Y(6%)-Mn co-doping. A minimal contribution from the Pbam phase was also observed at higher Y (12%). Co-doped compounds exhibit canted ferromagnetic behavior with a significant increase in the saturation magnetization (M s) of 1.28 emu/g when (Y, Mn) = (0.12 , 0.05). Dielectric measurements at different temperatures ranging between 30 ° C and 210 ° C in a wide frequency range of 1 Hz–1 MHz were investigated. Impedance study is useful to understand the correlation of grain and grain boundary with electrical properties. The grain and grain boundary contribution to electrical parameters was presented with equivalent R-C circuit. Furthermore, electrical properties such as complex electrical modulus and electrical conductivity analysis clearly emphasize the substitution of Y and Mn, leading to a significant change in BiFe O 3 ceramic. [ABSTRACT FROM AUTHOR]

In order to tailor the multiferroic as well as dielectric properties, we have synthesized BiFeO3 (BFO) and Ni-doped BFO nanoparticles of composition BiFe1-xNixO3 (0 ≤ x ≤ 0.07) via the sol-gel method. The influence of Ni-doping at the Fe site of BiFeO3 on the structural, dielectric, and multiferroic properties was investigated via various characterization techniques such as Raman spectroscopy, vibrating sample magnetometer, polarization-electric field (P-E) loop tracer, and LCR meter. The Raman spectra reveal the rhombohedral distorted perovskite structure of the samples in the R3c space group. The frequency dependent dielectric measurements at room temperature show that the dielectric constant for the pristine sample is an order of magnitude lower than the 1% Ni-doped BFO sample. It is also evident that the ac conductivity increases with the increase in frequency as well as Ni content. Further, the universal dielectric response (UDR) phenomenon is responsible for the dielectric behavior of all the samples in the whole frequency range except for the BiFeO3 and BiFe0.97Ni0.03O3 samples. These samples exhibit deviation from UDR phenomenon at higher frequencies. The room temperature hysteresis (M-H) loops exhibit the saturation in magnetization at higher magnetic fields. The result demonstrates a significant influence on the saturation magnetization with the Ni doping in BFO, prompting the ferromagnetic nature of the samples. The saturation magnetization of the 7% Ni-doped sample is approximately six times higher than the pristine one. The saturated P-E hysteresis loops establish the ferroelectric nature of the synthesized samples that are enhanced significantly on Ni doping. Thus, the doping of Ni in BiFeO3 improves the multiferroic properties of the matrix. [ABSTRACT FROM AUTHOR]

Multiferroic composites of (1-x)GaFeO3-(x)Co0.5Zn0.5Fe2O4 with x = 0.0, 0.1, 0.2, and 1 were prepared using a conventional solid state reaction method. The X-ray diffraction patterns confirmed that the composites consisted of cubic spinel Co0.5Zn0.5Fe2O4 and orthorhombic GaFeO3 phases. The coexistence of both magnetic and ferroelectric orderings at ambient temperature was confirmed by measuring M-H and P-E loops. The inclusion of Co0.5Zn0.5Fe2O4 enhanced magnetization and dielectric constant, as well as improved the ferroelectric properties of GaFeO3. The leakage current (9.33 × 10−8 A/cm2) of composite (x = 0.20) is found to be much lower as compared to pure GaFeO3. The value of saturation magnetization increased to 30.6 emu/g at 300 K. This large enhancement of magnetization, as well as the presence of ferroelectricity, is promising for enabling future magnetoelectric applications. [ABSTRACT FROM AUTHOR]

Multiferroics, showing the coexistence of two or more ferroic orderings at room temperature, could harness a revolution in multifunctional devices. However, most of the multiferroic compounds known to date are not magnetically and electrically ordered at ambient conditions, so the discovery of new materials is pivotal to allow the development of the field. In this work, we show that BaFe2O4 is a previously unrecognized room temperature multiferroic. X-ray and neutron diffraction allowed to reveal the polar crystal structure of the compound as well as its antiferromagnetic behavior, confirmed by bulk magnetometry characterizations. Piezo force microscopy and electrical measurements show the polarization to be switchable by the application of an external field, while symmetry analysis and calculations based on density functional theory reveal the improper nature of the ferroelectric component. Considering the present findings, we propose BaFe2O4 as a Bi- and Pb-free model for the search of new advanced multiferroic materials. The application of multiferroics is often limited by low ordering temperatures. Here, the authors show that BaFe2O4 is a room temperature antiferromagnet with improper ferroelectricity, suggesting it as a playground for the study of multiferroicity. [ABSTRACT FROM AUTHOR]

Multiferroic materials with coexisting ferroelectric and ferromagnetic orders have attracted much attention due to the magnetoelectric coupling opening alternative prospects for electronic devices. Composite multiferroics containing separate ferroelectric and ferromagnetic components are a promising alternative to the single-phase counterparts. Composite multiferroic structures comprising HfO2-based ferroelectrics are potentially feasible for technological applications. Here, this study reports on the experiments aiming at the manifestation of magnetoelectric coupling at Fe/Hf0.5Zr0.5O2 (HZO) interface. Using synchrotron based 57Fe Mössbauer spectroscopy technique in operando, this study probes element-selectively the local magnetic properties of a nanometer-thick enriched 57Fe marker layer in functional Pt/57Fe/HZO/TiN capacitors and demonstrates the evidence of the ferroelectric polarization effect on the a-Fe magnetic response. Besides a-Fe exhibiting a magnetoelectric coupling, both ferromagnetic and superparamagnetic Fe3O4 components are found in the Mössbauer spectra, apparently originating from the oxygen or OH- ions penetrating ultrathin Pt overlayer during crystallization annealing of HZO. The observed effect as well as the electronic band lineup of the Fe/HZO interface elucidated from synchrotron based hard X-ray photoemission spectroscopy measurements are interpreted in terms of charge-mediated magnetoelectric coupling at the Fe/HfO2 interface driven by ferroelectric HZO polarization reversal. [ABSTRACT FROM AUTHOR]

This paper will provide a brief overview of the unique multiferroic material Bismuth ferrite (BFO). Considering that Bismuth ferrite is a unique material which possesses both ferroelectric and magnetic properties at room temperature, the uniqueness of Bismuth ferrite material will be discussed. Fundamental properties of the material including electrical and ferromagnetic properties also will be mentioned in this paper. Electrical properties include characterization of basic parameters considering the electrical resistivity and leakage current. Ferromagnetic properties involve the description of magnetic hysteresis characterization. Bismuth ferrite can be fabricated in a different form. The common forms will be mentioned and include powder, thin films and nanostructures. The most popular method of producing thin films based on BFO materials will be described and compared. Finally, the perspectives and potential applications of the material will be highlighted. [ABSTRACT FROM AUTHOR]

Ca 3 (Ti 1- x Co x) 2 O 7 ceramics were prepared by a tartaric acid sol-gel method and sintered in an oxygen atmosphere. The introduction of Co2+/Co3+ as acceptor dopants leads to the formation of more oxygen vacancies and defect dipoles in Ca 3 (Ti 1- x Co x) 2 O 7 ceramics. Oxygen vacancy and defect dipoles lead to the transition of dielectric, leakage, and ferroelectric behaviors of Ca 3 (Ti 1- x Co x) 2 O 7 ceramics. The coexistence of hybrid improper ferroelectricity and ferromagnetism at room temperature in Ca 3 (Ti 1- x Co x) 2 O 7 ceramics has been successfully realized through the superexchange interaction of Co–O–Co. Ca 3 (Ti 1- x Co x) 2 O 7 ceramics exhibit superior ferroelectricity (the remnant polarization is 3.29 μC/cm2) and enhanced ferromagnetism (the remnant magnetization reaches 6.4×10−3 emu/g). This strategy based on the introduction of transition metal ions with unfilled 3d shells at B sites is an important approach to realize novel room-temperature single-phase multiferroic materials for Ca 3 Ti 2 O 7 -based materials. [ABSTRACT FROM AUTHOR]

The possibilities provided by the use of circularly polarized X rays in transmission and diffraction geometry for studying the properties of noncentrosymmetric crystals (electronic state, optical activity, absolute chirality, and distribution of chiral domains in multiferroics) are considered. [ABSTRACT FROM AUTHOR]

This paper presents the research results of multiferroic ceramic composites obtained with three sintering methods, i.e., free sintering FS (pressureless), hot pressing HP, and spark plasma sintering SPS. The multiferroic composite was obtained by combining a ferroelectric material of the PZT-type (90%) and zinc-nickel ferrite (10%). Research has shown that the combination of a magnetic material and ferroelectric materials maintains the multiferroic good ferroelectric and magnetic properties of the composites for all sintering methods. A sample sintered with the HP hot pressing method exhibits the best parameters. In the HP method, the composite sample has high permittivity, equal to 910 (at room temperature) and 7850 (at the phase transition temperature), residual polarization 2.80 µC/cm2, a coercive field of 0.95 kV/mm, and the magnetization of 5.3 and 4.95 Am2/kg at −268 °C and RT, respectively. Optimal technological process conditions are ensured by the HP method, improving the sinterability of the ceramic sinter which obtains high density and proper material compaction. In the case of the SPS method, the sintering conditions do not allow for homogeneous growth of the ferroelectric and magnetic component grains, increasing the formation of internal pores. On the other hand, in the FS method, high temperatures favor excessive grain growth and an increase in the heterogeneity of their size. In obtaining optimal performance parameters of multiferroic composites and maintaining their stability, hot pressing is the most effective of the presented sintering methods. [ABSTRACT FROM AUTHOR]

The nanoindentation technique plays a significant role in characterizing the mechanical properties of materials at nanoscale, where the adhesion effect becomes very prominent due to the high surface-to-volume ratio. For this paper, the classical adhesion theories were generalized to study the contact behaviors of various piezoelectric materials indented by conical punches with different electric properties. With the use of the Hankel integral transform, dual integral equations, and superposing principle, the closed-form solutions of the physical fields for the Johnson-Kendall-Roberts (JKR) and Maugis-Dugdale (M-D) models were obtained, respectively. The contribution of the electrical energy to the energy release rate under the conducting punch was taken into consideration. The relationships between the contact radius, the indentation load, and the indentation depth were set up using the total energy method for the JKR model and the Griffith energy balance for the M-D model, respectively. Numerical results indicate that increasing the half cone angle of the conical punch enhances the adhesion effect, which can significantly affect the accuracy of the results of characterization in nanoindentation tests. It was found that the effect of electric potential on adhesion behaviors is sensitive to different material properties, which are not revealed in the existing studies of axisymmetric adhesive contact of piezoelectric materials and multiferroic composite materials. The load-displacement curves under conical punches with different half cone angles have very different slopes. These results indicate that the half cone angle has a prominent effect on the characterization of mechanical properties of piezoelectric solids in nanoindentation tests. [ABSTRACT FROM AUTHOR]

Bismuth ferrite (BiFeO3 or BFO), is an extremely promising multiferroic material having broad range of applications. In the present study, we investigated the optimization of annealing temperature for the preparation of pure phase bismuth ferrite using quantitative Rietveld analysis of XRD patterns. The rhombohedral structure was confirmed by X-ray diffraction with R3c space group as a primary phase (pure BFO) along with a cubic secondary phase (Bi25FeO40) having space group I23. The quantitative analysis of refine data shows the decrease in the values of fitting parameters in case of double refinement and hence convergence towards the best fitting. Also, with the increase in annealing temperature, very nominal decrease in phase percentage of secondary phase was observed. At annealing temperature of 780 °C, the intensity of (110) planes suddenly becomes more in comparison to (104) planes. The average crystallite size of samples was calculated using Scherrer formula, W–H plot method, and Rietveld method, and lattice strain was derived from the W–H plot method. Overall, the crystallite size increases with the increase in annealing temperature. It has been also observed that the strain, lattice parameters, unit cell volume, and effective bond lengths decrease with the increase in annealing temperature, but no significant change was observed in bond angles with the variation in annealing temperature. [ABSTRACT FROM AUTHOR]

Multiferroic BiFeO3 and 10% La/Mn-doped BiFeO3 powder samples were synthesized by conventional hydrothermal method to study the substitution at different sites driven by structural transformation and magnetic property in BiFeO3. Room-temperature X-ray diffraction (XRD) patterns identified the rhombohedral R3c symmetry for all samples and further confirmed by the Bi-L3 edge and Fe-K edge X-ray absorption fine structure (XAFS) spectra. However, a nanoscale phase transition from R3c structure to orthorhombic symmetry was revealed by the La-L3 edge XAFS. In contrast, the Mn-doped BiFeO3 remained R3c crystal structure. Besides, the variation of magnetism due to A-site and B-site substitution in BiFeO3 was observed in the magnetic hysteresis loops. [ABSTRACT FROM AUTHOR]

The magnetic and electrical properties of the system of solid solutions (1 − х)BiFeO3–xRMnO3, where R = Sc or Y (0.05 ≤ x ≤ 0.4), synthesized by nitrate technology are studied. The presence of ferromagnetic ordering in these ceramic multiferroics at room temperature is established. The concentration dependences of the magnetization M(x) for both systems of solid solutions have an extremum; the maximum magnetization is observed in the compositions at x = 0.15. The coercivity field Hc for these compositions is of ≅ 5-90 Oe. The dielectric permeability of the samples (at T = 300 K) varies in the range ≅ 17-297 at a frequency of 1 kHz, and at a frequency of 1 MHz, it varies in the range ≅ 7-25. [ABSTRACT FROM AUTHOR]

Nanoparticles with small diameters and large surface areas have potential advantages and are actively utilized in various fields related to biomedical and catalytic applications. Multifunctional applications can be achieved by endowing nanoparticles with piezoelectric, quantum dot, magnetothermal, and piezoluminescent properties. In particular, multiferroic magnetoelectric nanoparticles (MENPs) can generate electricity by coupling piezoelectric and magnetostrictive properties when an external magnetic field, which is harmless to the human body, is applied. In this regard, magnetoelectricity (ME) induced by a magnetic field makes MENPs useful for various biomedical and electrocatalytic applications. The ME voltage coefficients, which express the efficiency of energy conversion from magnetic field to electricity, show differences depending on the setup for ME measurements of MENPs. Therefore, numerous attempts have been made to optimize the ME characterization method to reduce measurement errors resulting from charge leakages caused by the specimen preparation, as well as to investigate the ME effect of a single nanoparticle. Our review is focused on the structures, syntheses (hydrothermal and sol–gel methods), activation mechanism, and measurement of magnetoelectricity, as well as applications, of core–shell MENPs. [ABSTRACT FROM AUTHOR]

Polymer-based multiferroics, combining magnetic and piezoelectric properties, are studied experimentally—from synthesis to multi-parameter characterization—in view of their prospects for fabricating biocompatible scaffolds. The main advantage of these systems is facile generation of mechanical deformations and electric signals in response to external magnetic fields. Herein, we address the composites based on PVDF-TrFE polymer matrices filled with a combination of piezoelectric (BaTiO3, BTO) and/or ferrimagnetic (Zn0.25Co0.75Fe2O4, ZCFO) particles. It is shown that the presence of BTO micron-size particles favors stripe-type structuring of the ZCFO filler and enhances the magnetoelectric response of the sample up to 18.6 mV/(cm∙Oe). Besides that, the admixing of BTO particles is crucial because the mechanical properties of the composite filled with only ZCFO is much less efficient in transforming magnetic excitations into the mechanical and electric responses. Attention is focused on the local surfacial mechanical properties since those, to a great extent, determine the fate of stem cells cultivated on these surfaces. The nano-indentation tests are accomplished with the aid of scanning probe microscopy technique. With their proven suitable mechanical properties, a high level of magnetoelectric conversion and also biocompatibility, the composites of the considered type are enticing as the materials for multiferroic-based polymer scaffolds. [ABSTRACT FROM AUTHOR]

Charge mediated magnetoelectric coupling mechanism in artificial multiferroics originates from interfacial charge modulation or ionic movement at a magnetic/dielectric interface. Despite the existence of several dielectric/ferroelectric systems that can be used in charge mediated artificial multiferroic systems, producing suitable systems with fast time responses still remains a challenge. Here we characterize the frequency response of stoichiometric and non-stoichiometric (low strain) Si 3 N 4 thin film membranes, which can potentially be used as the dielectric layer in magnetoelectric devices, to determine the impact of depletion layers, charge traps and defect mobility on the high frequency (up to 100 MHz) interfacial charge modulation via screening. We find that the dielectric/magnetoelectric properties are largely dominated by extrinsic doping due to point defects. In particular, we find that non-stoichiometric Si 3 N 4 has a dielectric behaviour that is dominated by charge traps and/or mobile ions. However, stoichiometric Si 3 N 4 membranes show a reversible response to the applied bias electric field consistent with a doped semiconductor behaviour; at high frequencies, the intrinsic dielectric behaviour is reached, indicating that it may be suitable for high frequency magnetoelectric device applications. Our results show that minimising the impact of defects on the dielectric properties of magnetoelectric heterostructures is an important prerequisite for obtaining a high frequency magnetoelectric response. [ABSTRACT FROM AUTHOR]

Magnetoelectric (ME) sensors are an important tool to detect weak magnetic fields in the industry; however, to date, there are no high-quality ME sensors available for high-temperature environments such as engines, deep underground, and outer space. Here, a 0.364BiScO3–0.636PbTiO3 piezoelectric ceramic and Terfenol-D alloy with a Curie temperature of 450 and 380 °C, respectively, were bonded together by an inorganic glue to achieve a high-temperature ME sensor. The ceramic shows a piezoelectric d33 coefficient of 780 pC/N at 420 °C, and the inorganic glue has a high maximum stress of 9.12 MPa even at 300 °C. As a result, the sensor exhibits the maximum ME coefficient αE of 2.008, ∼1.455, and ∼0.906 V cm−1 Oe−1 at 20, 200, and 350 °C, respectively. Most importantly, the magnetic field detecting precision is as small as 42 nT at 20–350 °C. The ME sensor provides an effective solution for the detection of weak magnetic fields in harsh environments. [ABSTRACT FROM AUTHOR]

Coupling of multiphysics including electrodynamics, elastodynamics, magnetodynamics, and electromagnetic (EM) radiation is involved in the operating process of bulk acoustic wave (BAW) antenna. There is still no good way to design the structure and evaluate the performance of the antenna in theory. Therefore, the multiphysics dynamic coupling model of the antenna is constructed by uniting Newton’s equation for acoustic wave, Maxwell’s equation for EM wave, and Landau–Lifshitz–Gilbert (LLG) equation for spin wave with constitutive relations of multiferroic materials to discuss the dispersion law of permeability and magnetomechanical coupling factor for the magnetostrictive layer. The importance of consistency between ferromagnetic resonance (FMR) frequency and BAW resonant frequency is demonstrated. The analysis shows that both increasing the anisotropic field or the saturation magnetization and decreasing the FMR linewidth are beneficial to improving the internal energy conversion efficiency and the average radiated power for BAW antenna. In addition, a micromagnetic module is introduced into finite element analysis (FEA) software to simulate the precession of unit magnetic moment at different frequencies. Thus, the analytical model is verified from the perspective of power absorption. [ABSTRACT FROM AUTHOR]

Optical second harmonic generation (SHG) is a sensitive and powerful technique to probe various symmetry breaking, especially ferroelectric/magnetic domains, in artificial thin films or heterostructures. In a wide range of ferroelectric crystals, a non‐trivial broken symmetry will emerge at domain boundaries, however, the contribution of such symmetry breaking to SHG is often neglected due to its random orientation. Here, a co‐polarized SHG effect from the well‐aligned domain wall arrays is observed in BiFeO3 thin films. This SHG component is highly dependent on the local orientation of the wall arrays, and its polarization feature reveals the Néel‐like evolution of electric polar vectors in the wall region. Based on this intriguing effect, mixed‐phase patches with four possible orientations in the quasi‐tetragonal stripes are identified by polarization‐sensitive SHG mapping. These findings not only clarify a critical SHG contribution in this multiferroic material, but also demonstrate an optical approach for exploring phase‐determined function unit. [ABSTRACT FROM AUTHOR]

We use density functional theory (DFT) calculations to show that oxygen vacancies ( v O ) and mobility induce noncentrosymmetric polar structures in SrTi 1 − x − y Fe x Co y O 3 − δ (STFC, x = y = 0.125 ) with δ = { 0.125 , 0.25 } , enhance the saturation magnetization, and give rise to large changes in the electric polarization | Δ P | . We present an intuitive set of rules to describe the properties of STFC, which are based on the interplay between (Co/Fe)- v O defects, magnetic cation coordination, and topological vacancy disorder. STFC structures consist of layered crystals with sheets of linearly organized O 4 , 5 , 6 -coordinated Fe–Co pairs, sandwiched with layers of O 5 -coordinated Ti. (Co/Fe)- v O defects are the source of crystal distortions, cation off-centering and bending of the oxygen octahedra which, considering the charge redistribution mediated by v O and the cations' electronegativity and valence states, triggers an effective electric polarization. Oxygen migration for δ = 0.125 leads to | Δ P | >∼10 µC/cm 2 due to quantum-of-polarization differences between δ = 0.125 structures. Increasing the oxygen deficiency to δ = 0.25 yields | Δ P | , the O migration of which resolved polarization for δ = 0.25 is > ∼ 3 µC/cm 2 . Magnetism is dominated by the Fe,Co spin states for δ = 0.125 , and there is a contribution from Ti magnetic moments (∼1 μ B ) for δ = 0.25 . Magnetic and electric order parameters change for variations of δ or oxygen migration for a given oxygen deficiency. Our results capture characteristics observed in the end members of the series SrTi(Co,Fe)O 3 , and suggest the existence of a broader set of rules for oxygen-deficient multiferroic oxides. [ABSTRACT FROM AUTHOR]

The main idea of this paper is to incorporate and solidify magnetic nanoparticles of CoFe2O4 with a size less than 20 nm in a synthesized porous alumina membrane. In such a configuration, all the magnetic particles are oriented according to an external magnetic field and stay in this orientation even without a magnetic field after the solidification of the matrix. The procedure consists of three preliminary steps. First, we mixed the well-dispersed CoFe2O4 nanoparticles in a hexane solvent, to have a state transition from the liquid (CoFe2O4 nanoparticles surrounded by organic layer and dispersed in hexane) to the solid one of CoFe2O4. Second, we incorporate CoFe2O4 nanoparticles into the alumina membrane pores. Finally, a step of a heat treatment compatible with the magnetic nanoparticles is necessary to evaporate all the organic compounds. The insertion of nanoparticles has been done with the help of an external magnetic field. This work presents a new technique to synthesis a solid regular array of cobalt ferrite nanorods. After the removal of AAO membrane, cobalt ferrite nanorods can be used as a host for another material to prepare a nanocomposite material like extrinsic multiferroic. [ABSTRACT FROM AUTHOR]

Achieving self‐assembling structures that exhibit emergent properties and functionalities is one of the holy grails in nanotechnology and holds great promise for a wide range of potential applications. Herein, a self‐assembled LuFeO3–(1/3)LuFe2O4–LuFeO3 heterostructure that consists of two model multiferroics, i.e., hexagonal LuFeO3 and rhombohedral LuFe2O4, is reported in single‐layer epitaxial LuFeO3 thin films. Atomic‐scale electron microscopy investigations reveal the spontaneous organization of ferroelectric polarization in each building block, which forms a series of polar configurations. Specifically, the charge and lattice of neighboring LuFeO3 and LuFe2O4 blocks are closely coupled with competing degrees of freedom. A combination of the quantitative analysis of atomically resolved images and spectroscopy with theoretical calculations determines how charge‐ordering‐induced polarization accommodates charge naturality across the interfaces to reduce the system energy and unravels the formation mechanism of this heterostructure. The results point to the possibilities of generation and control of multiferroic self‐assembled systems, which may provide a basis for engineering novel materials with emergent properties. [ABSTRACT FROM AUTHOR]

Double perovskites with cation ordering allow the coexistence of ferroelectricity and magnetization in the same phase, and thus become a good candidate for room-temperature multiferroic materials. In this paper, we successfully synthesized A- and B-site ordered double perovskites NaLnBWO 6 (Ln = La, Nd, and B Mg, Mn) ceramics, and investigated their microstructure by combining X-ray diffraction, aberration-corrected scanning transmission electron microscopy, and optical second harmonic generation measurements. At room temperature, both NaLaMgWO 6 and NaNdMgWO 6 ceramics possess the space group of P 2 1 / m , while NaLaMnWO 6 has a polar crystal structure (P 2 1) without inversion symmetry. All three samples exhibit the A-site layered ordering and B-site rock-salt ordering as directly imaged by the HAADF-STEM images. The observed structural domains arising from the cation ordering well explain the nonswitchable ferroelectric polarization due to a large energy barrier. These findings suggest that it is necessary to eliminate structural domains during the sample synthesis for obtaining large ferroelectric polarization in double perovskites. [ABSTRACT FROM AUTHOR]

Room-temperature single-phase multiferroic materials have attracted the considerable attention of may scientists due to their technological applications in the next-generation electronic devices. Here, we report the structural evolution and its relationship with the ferroelectric and magnetic properties of Aurivillius Bi 3.25 Sm 0.75 Ti (3-x) (Fe,Co) x O 12 (BSmT:FCx); for (0≤x ≤ 0.4) ceramics to elucidate the room-temperature multiferroics induced by Fe/Co co-substitution. The XRD analysis and structural refinements reveal that incorporating of Co, and Fe ions into Ti sites of BSmT host lattices gives rise to a single orthorhombic phase with no evidence of secondary phases. The X-ray photoelectron spectroscopy (XPS) spectra indicate the existence of oxygen vacancies in the investigated samples. Pure BiT samples exhibit diamagnetic behavior, while BSmT:FCx; for (0≤x ≤ 0.4) exhibits ferromagnetic behavior at room temperature. As a result, the sample with x = 0.4 displayed the highest remnant and saturation magnetization values. It is believed that the occurrence of magnetism causes by the magnetic double exchange interaction between the non-equivalent magnetic ions and oxygen. The reversible polarization induced by an electric field indicates the ferroelectric character of the ceramics at room temperature. The co-substituting samples show unsaturated P-E hysteresis loops, which could be caused by the domain pinning induced by the accumulation of oxygen vacancies near the domain boundaries. We expect these compounds are promising for developing electronic devices for future applications. [ABSTRACT FROM AUTHOR]

Understanding the dielectric relaxation properties of multiferroic hexaferrite thin films is crucial for device applications. This work investigates the dielectric relaxation characteristics (DRC) of multiferroic hexaferrite BaFe 10.2 Sc 1.8 O 19 (BFSO) thin film under multi-fields. The alternative driving voltage and biasing voltage V b were found to have significant effects on the DRC of BFSO/electrode interface dipoles, but negligible effects on the intrinsic dipoles in BFSO film. The DRC mechanism of a BFSO film capacitor under a magnetic field is opposite to that of V b ; is dominated by intrinsic dipoles in BFSO, and is thermally activated. The temperature-dependent magnetodielectric spectra confirm that multiferroic dipoles in BFSO significantly impact the DRC of the capacitor, which is different from the DRC of nonmagnetic ceramic capacitors. The above findings can clarify the DRC mechanisms and integration of multiferroic hexaferrite thin films in magnetoelectric devices. [ABSTRACT FROM AUTHOR]

Enhanced magnetic and ferroelectric properties have been observed in Hf substituted Bi0.97K0.9Fe1−xHf(3/4)xO3 (0.00 ≤ x ≤ 0.20) nanocrystalline multiferroics which were synthesized via auto combustion sol–gel method. Citric acid was used as a solvent. Structural investigation confirmed the development of pure perovskite rhombohedral distorted phase. The enlargement in cell volume was observed with K–Hf substitution due to lattice distortion and the ionic radii of substituents. Ferroelectric loops showed that maximum polarization (Pmax) was inclined from 0.000376 to 0.391 µc/cm2 as well as remanent polarization (Pr) from 1.000815 to 5.39 µc/cm2. This was due to Hf–K contents which altered Fe–O bond length and increase disturbance in FeO6 octahedra which increase polarization. High values of saturation magnetization (Ms = 4.79 emu/g) and remanent magnetization (Mr = 1.7 emu/g) was attributed to disturbance in antiferromagnetic spin modulated cycloid (λ = 62 nm) structure. Enhancements of magnetic properties along with the formation of P-E loops make these multiferroic nanomaterials the best candidates for magnetoelectric RAMS. [ABSTRACT FROM AUTHOR]

Two-dimensional multiferroic materials have garnered broad interests attributed to their magnetoelectric properties and multifunctional applications. Multiferroic heterostructures have been realized, nevertheless, the direct coupling between ferroelectric and ferromagnetic order in a single material still remains challenging, especially for two-dimensional materials. Here, we develop a physical vapor deposition approach to synthesize two-dimensional p-doped SnSe. The local phase segregation of SnSe2 microdomains and accompanying interfacial charge transfer results in the emergence of degenerate semiconductor and metallic feature in SnSe. Intriguingly, the room-temperature ferrimagnetism has been demonstrated in two-dimensional p-doped SnSe with the Curie temperature approaching to ~337 K. Meanwhile, the ferroelectricity is maintained even under the depolarizing field introduced by SnSe2. The coexistence of ferrimagnetism and ferroelectricity in two-dimensional p-doped SnSe verifies its multiferroic feature. This work presents a significant advance for exploring the magnetoelectric coupling in two-dimensional limit and constructing high-performance logic devices to extend Moore's law. 2D multiferroic materials have garnered broad interests due to their magnetoelectric properties and multifunctional applications. Here, the authors discover a multiferroic feature in physical vapor deposition synthesized 2D metallic p-doped SnSe. [ABSTRACT FROM AUTHOR]

BiFeO3 is a multiferroic material with a perovskite structure that has a lot of potential for use in sensors and transducers. However, obtaining pure single-phase BiFeO3 ceramic with a low electrical conductivity via solid-state reactions remains a problem that limits its application. In this work, the suppression of secondary phases in BiFeO3 was studied by varying the compositional parameters and the sintering temperature. The addition of 1% Bi2O3 to the stoichiometric precursor mixture prevented the formation of secondary phases observed when sintering stoichiometric precursors. The pure phase ceramic had a p-type conductivity and a three-decade lower electrical conductivity as measured by impedance spectroscopy. Annealing of optimally synthesized material at different partial pressures of oxygen in an oxygen–nitrogen gas atmosphere showed that the reason for this type of conductivity lies in the high concentration of defects associated with oxygen. By annealing in various mixtures of nitrogen and oxygen, it is possible to control the concentration of these defects and hence the conductivity, which can go down another two decades. At a pO2  ≤ 10 % , the conductivity is determined by intrinsic charge carriers in the material itself. [ABSTRACT FROM AUTHOR]

We systematically studied the structure, electronic, elastic and optical properties of BiGaO3 type perovskite cubes. We also report the calculation of all properties listed in the title of GGA-PBE approximation to BiGaO3. This material has a band gap which can be considered as an indirect band gap. The maximum valence band is represented by the M point (VBM), whereas the conduction band is represented by the X point (CBM)The electronic structure of BiGaO3 shows that it has a semiconductor indirect band gap of 1.37 eV. The elastic constant was determined in equilibrium confirming its accuracy. The bulk, shear, and Young's modulus were all extracted from the data. Poisson's ratio was also found. The confirmed structural parameters were in good agreement with the previously calculated experimental data. Our research suggests that BiGaO3 is a promising piezoelectric, multiferroic, ferroelectric, and photo catalytic material. [ABSTRACT FROM AUTHOR]

Fe-substituted YFexCr1−xO3 crystalline compounds show promising magnetic and multiferroic properties. Here we report the synthesis and characterization of several compositions from this series. Using the autocombustion route, various compositions (x = 0.25, 0.50, 0.6, 0.75, 0.9, and 1) were synthesized as high-quality crystalline powders. In order to obtain microscopic and atomic information about their structure and magnetism, characterization was performed using room temperature X-ray diffraction and energy dispersion analysis as well as temperature-dependent neutron diffraction, magnetometry, and 57Fe Mössbauer spectrometry. Rietveld analysis of the diffraction data revealed a crystallite size of 84 (8) nm for YFeO3, while energy dispersion analysis indicated compositions close to the nominal compositions. The magnetic results suggested an enhancement of the weak ferromagnetism for the YFeO3 phase due to two contributions. First, a high magnetocrystalline anisotropy was associated with the crystalline character that favored a unique high canting angle of the antiferromagnetic phase (13°), as indicated by the neutron diffraction analysis. This was also evidenced by the high magnetic hysteresis curves up to 90 kOe by a remarkable high critical coercivity value of 46.7 kOe at room temperature. Second, the Dzyaloshinskii–Moriya interactions between homogenous and heterogeneous magnetic pairs resulted from the inhomogeneous distribution of Fe3+ and Cr3+ ions, as indicated by 57Fe Mössbauer studies. Together, these results point to new methods of controlling the magnetic properties of these materials. [ABSTRACT FROM AUTHOR]

The magnetic circuit has been a popular and powerful tool to analyze the magnetic field in electromagnetic devices for a long history. However, in the conventional magnetic circuit there is only one kind of component namely reluctance, which cannot analyze the phase shift or the amplitude attenuation of the alternating flux in electromagnetic devices. In this article, a new physical concept of magnetic-inductance is proposed, based on which the alternating-flux magnetic circuit theory including two kinds of components namely reluctance and magnetic-inductance has been developed. Furthermore, the virtual magnetic power is defined as the analogue of electric power, and the magnetoelectric power law is derived for magnetic circuits. Using the proposed magnetic circuit theory with magnetic-inductance, the relationship between the electric power and the virtual magnetic power is revealed and the long-lasting confusions in previous magnetic circuit methods, i.e., power calculation and phase shifts of magnetic variables, are clarified. By experiments, the magnetic-inductance and the magnetoelectric power law are validated, and their applications in eddy current loss analysis and B-H curve estimation in magnetic materials are demonstrated. [ABSTRACT FROM AUTHOR]

This work promotes the room temperature energy storage properties of the multiferroics. In this approach, impacts of PrFeO3 doping on PT-based solid solutions (Pb 1 − x Pr x Ti 1 − x Fe x O3, x = 0.21, 0.22, 0.23, 0.24, 0.25 and 0.26) have been explored. X-ray diffraction (XRD) patterns were used to estimate the crystallographic parameters, confirming the single phase tetragonal structure. The ferroelectric Curie temperature ( T c FE ) is observed to drop from 410 K to below room temperature as the Pr concentration increases. The ferroelectric P-E loops were used to determine the energy storage values at room temperature. The sample x = 0.24 achieved the maximum value of energy storage density of 362.25 mJ/cm3 with the efficiency of 40.5%. The ferroelectric P-E loops were used to determine the energy storage values at room temperature. The validity of magnetoelectric coupling in all samples was confirmed by magneto-dielectric studies and found that the sample x = 0.24 shows the maximum response with the coupling coefficient (γ) = 15.54 g2/emu2. [ABSTRACT FROM AUTHOR]

• Focused on advances, opportunities with future scope, and challenges in electric field-controlled magnetism. • Crucial role of multiferroic heterostructure to improve the magnetoelectric coupling. • Challenges like substrate clamping and thin film limitations addressed, which can be overcome in the future. • Novel multiferroic materials are concentrated in multiferroic heterostructure with improved magnetoelectric coupling. This review article presents the recent advances in electric field-controlled magnetism using multiferroic heterostructures. Electric field-manipulated spin magnetic moments are important from both basic science and application points of view. Multiferroic materials, where ferroelectricity and magnetic orderings coexist, offer exciting and novel prospects of electric control of magnetic properties. Electric field control of magnetism is essential to developing energy-efficient and versatile spintronic devices that can revolutionize data storage, magnetic sensing, and many other applications. Thus, we will review recent progress in electric field control of magnetism in multiferroic heterostructures and its advanced characterization to identify potential applications, remaining challenges, and future prospects. Through this review, we hope the reader will gain knowledge on the recent advances in electric field-controlled magnetism and its challenges that can lead to the practical realization of new generation devices in the future. [ABSTRACT FROM AUTHOR]

The Bi 1- x La x Fe 1- y Cr y O 3 (x = 0.00, 0.06; y = 0.00, 0.03, 0.06, 0.09, 0.12) nanomaterials have been synthesized using the simple solvo-thermal technique. The Rietveld refinement of XRD analysis using FullProf Software confirms that all synthesized materials follow rhombohedral perovskite crystal structure of R3 C space group. The dielectric and ac conductivity data are analyzed to understand the role of grain and grain boundary contributions. The enhancement of magnetic properties has been observed from SQUID measurement for the co-doped samples at room temperature. Also, a significant improvement in polarization has been observed for the doped nanocompounds from the ferroelectric hysteresis loop. The magneto-dielectric study reveals a large improvement in our co-doped BFO nanomaterials and the value is nearly three times of those reported earlier. The calculated energy storage efficiency for the co-doped samples are found to have as high as 51 %. The sample with x = 0.06 and y = 0.09 with a magneto dielectric coefficient of around 30 % and energy storage efficiency of 35 % is the most suitable for both spintronic and energy storage devices. • Synthesis of double-doped BiFeO 3 nanomaterials through solvothermal process. • The Rietveld refinement of XRD confirms R3 C group rhombohedral crystal symmetry. • Enhancement of magneto-dielectric effect is observed. • Improvement of multiferroic properties has been found. • Proper doping concentration is useful for spintronic and energy storage applications. [ABSTRACT FROM AUTHOR]

Hybrid improper ferroelectricity Ca 3 Mn 2 O 7 is the promising multiferroic materials, which has attracted considerable attention due to their potential applications in areas such as electronic devices and storage media. The magnetic and electric properties of the layered perovskite Ca 3 Mn 2 O 7 ceramics with different proportions of single-layer Ca 2 MnO 4 phase synthesized by solid state reaction within adjusting the sintering temperature have been investigated. The x-ray diffraction patterns and the characteristic of magnetic transition from magnetization curves show that the ratio of Ca 2 MnO 4 is reduced from 22.9 % of sintering at 1200 °C to 0 % of sintering at 1300 °C, which implies that the narrow suitable sintering temperature is the most factor for preparation of pure Ca 3 Mn 2 O 7 ceramic samples. The ferroelectricity of all samples was investigated and the ferroelectricity decreased with the increase of Ca 2 MnO 4 content due to the presence of non-ferroelectric Ca 2 MnO 4 phase. The magnetoelectric coupling effect was discussed by the magnetization induced from the electric field. The results speculated that a small amount of Ca 2 MnO 4 can improve the magnetoelectric coupling effect due to the interface effect in multiphase materials, which suggests that a new method to enhance the magnetoelectric coupling effect in Ca 3 Mn 2 O 7 system. • R–P ceramic materials Ca 3 Mn 2 O 7 with different proportions of single-layer Ca 2 MnO 4 were obtained by different sintering temperatures. • The coercivity of Ca 3 Mn 2 O 7 ceramic materials can be enhanced with certain amount of single-layer Ca 2 MnO 4. • The magnetoelectric coupling effect of Ca 3 Mn 2 O 7 ceramic material would be improved by small amount of single-layer Ca 2 MnO 4. [ABSTRACT FROM AUTHOR]

\nIMPACT STATEMENTFirst-principles calculations incorporating spin-orbit coupling are presented for a multiferroic material as a ferromagnetic/ferroelectric junction. We simulate the interface effect that cannot be described by the single-phase bulk. The in-plane uniaxial magnetic-anisotropy of Co2FeSi is observed when the ferroelectric domain is polarized parallel to the interface, whereas the magnetic anisotropy is significantly different in the plane for the electrical polarization perpendicular to the interface. While the single-phase effect dominates the main part of the modulation of the magnetic anisotropy, symmetry breaking due to the interfacial effect is observed in the ferromagnetic ultrathin films. The origin of the modulated magnetic-anisotropy can be attributed to the shifting of specific energy bands in Co2FeSi when the ferroelectric domain is modified.The origin of strain-induced magnetocrystalline anisotropy in multiferroic Co2FeSi/BaTiO3(001) heterostructures is clarified by first-principles electron theory. The magnetic anisotropy is modified by interface effects for ultrathin Co2FeSi films. [ABSTRACT FROM AUTHOR]