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Magnetodielectric (MD) materials are important for their ability to spin-charge conversion, magnetic field control of electric polarization and vice versa. Among these, two-dimensional (2D) van der Waals (vdW) magnetic materials are of particular interest due to the presence of magnetic anisotropy (MA) originating from the interaction between the magnetic moments and the crystal field. Also, these materials indicate a high degree of stability in the long-range spin order and may be described using suitable spin Hamiltonians of the Heisenberg, XY, or Ising type. Recent reports have suggested effective interactions between magnetization and electric polarization in 2D magnets. However, MD coupling studies on layered magnetic materials are still few. This review covers the fundamentals of magnetodielectric coupling by explaining related key terms. It includes the necessary conditions for having this coupling and sheds light on the possible physical mechanisms behind this coupling starting from phenomenological descriptions. Apart from that, this review classifies 2D magnetic materials into several categories for reaching out each and every class of materials. Additionally, this review summarizes recent advancements of some pioneer 2D magnetodielectric materials. Last but not the least, the current review provides possible research directions for enhancing magnetodielectric coupling in those and mentions the possibilities for future developments.&#xD., (© 2025 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)

Two-dimensional (2D) van der Waals magnets show strong interconnection between their electrical, magnetic, and structural properties. Here, the emergence of a luminescent transition is revealed upon crossing the Néel transition temperature of CrPS 4 , a layered antiferromagnetic semiconductor. This luminescent transition occurs above the lowest absorption level. The optical transitions are attributed to excited states of the t 2g orbitals of the Cr 3+ ions, which are influenced by the distortion of the octahedral crystal field. Specifically, the vicinity of the Néel temperature, the distortion switches from an anti-polar to a polar arrangement, thereby not only promoting an additional luminescent pathway but also significantly strengthening the static dipole moment detected by a marked enhancement in the intensity of the second harmonic generation. These results strongly encourage further investigation into the multiferroic properties and potential coupling mechanisms in CrPS 4 ., (© 2025 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Ultrafast optical manipulation of magnetic phenomena is an exciting achievement of mankind, expanding one's horizon of knowledge toward the functional nonequilibrium states. The dynamics acting on an extremely short timescale push the detection limits that reveal fascinating light-matter interactions for nonthermal creation of effective magnetic fields. While some cases are benchmarked by emergent transient behaviors, otherwise identifying the nonthermal effects remains challenging. Here, a femtosecond time-resolved resonant magnetic X-ray diffraction experiment is introduced, which uses an X-ray free-electron laser (XFEL) to distinguish between the effective field and the photoinduced thermal effect. It is observed that a multiferroic Y-type hexaferrite exhibits magnetic Bragg peak intensity oscillations manifesting entangled antiferromagnetic (AFM) and ferromagnetic (FM) Fourier components of a coherent AFM magnon. The magnon trajectory constructed in 3D space and time domains is decisive to evince ultrafast field formation preceding the lattice thermalization. A remarkable impact of photoexcitation across the electronic bandgap is directly unraveled, amplifying the photomagnetic coupling that is one of the highest among AFM dielectrics. Leveraging the above-bandgap photoexcitation, this energy-efficient optical process further suggests a novel photomagnetic control of ferroelectricity in multiferroics., (© 2023 The Authors. Advanced Materials published by Wiley-VCH GmbH.)

The discovery of a novel long-lived metastable skyrmion phase in the multiferroic insulator Cu 2 OSeO 3 visualized with Lorentz transmission electron microscopy for magnetic fields below the equilibrium skyrmion pocket is reported. This phase can be accessed by exciting the sample non-adiabatically with near-infrared femtosecond laser pulses and cannot be reached by any conventional field-cooling protocol, referred as a hidden phase. From the strong wavelength dependence of the photocreation process and via spin-dynamics simulations, the magnetoelastic effect is identified as the most likely photocreation mechanism. This effect results in a transient modification of the magnetic free energy landscape extending the equilibrium skyrmion pocket to lower magnetic fields. The evolution of the photoinduced phase is monitored for over 15 min and no decay is found. Because such a time is much longer than the duration of any transient effect induced by a laser pulse in a material, it is assumed that the newly discovered skyrmion state is stable for practical purposes, thus breaking ground for a novel approach to control magnetic state on demand at ultrafast timescales and drastically reducing heat dissipation relevant for next-generation spintronic devices., (© 2023 The Authors. Advanced Materials published by Wiley-VCH GmbH.)

Unlike any other nanoparticles known to date, magnetoelectric nanoparticles (MENPs) can generate relatively strong electric fields locally via the application of magnetic fields and, vice versa, have their magnetization change in response to an electric field from the microenvironment. Hence, MENPs can serve as a wireless two-way interface between man-made devices and physiological systems at the molecular level. With the recent development of room-temperature biocompatible MENPs, a number of novel potential medical applications have emerged. These applications include wireless brain stimulation and mapping/recording of neural activity in real-time, targeted delivery across the blood-brain barrier (BBB), tissue regeneration, high-specificity cancer cures, molecular-level rapid diagnostics, and others. Several independent in vivo studies, using mice and nonhuman primates models, demonstrated the capability to deliver MENPs in the brain across the BBB via intravenous injection or, alternatively, bypassing the BBB via intranasal inhalation of the nanoparticles. Wireless deep brain stimulation with MENPs was demonstrated both in vitro and in vivo in different rodents models by several independent groups. High-specificity cancer treatment methods as well as tissue regeneration approaches with MENPs were proposed and demonstrated in in vitro models. A number of in vitro and in vivo studies were dedicated to understand the underlying mechanisms of MENPs-based high-specificity targeted drug delivery via application of d.c. and a.c. magnetic fields. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Nanomedicine for Neurological Disease Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies., (© 2022 The Authors. WIREs Nanomedicine and Nanobiotechnology published by Wiley Periodicals LLC.)

The breaking of the out-of-plane symmetry makes a two-dimensional (2D) Janus monolayer a new platform to explore the coupling between ferroelectricity and ferromagnetism. Using density functional theory in combination with Monte Carlo simulations, we report a novel phase-switchable 2D multiferroic material VInSe 3 with large intrinsic out-of-plane spontaneous electric polarization and a high Curie temperature ( T c ). The structural transition energy barrier between the two phases is determined to be 0.4 eV, indicating the switchability of the electric polarizations and the potential ferroelectricity. Carrier doping can boost the Curie temperature above room temperature, attributing to the enhanced magnetic exchange interaction. A transition from the ferromagnetic (FM) state to the antiferromagnetic (AFM) state can be induced by carrier doping in octahedra-VInSe 3 , while FM coupling is well-preserved in tetrahedron-VInSe 3 low-dimensional monolayers but also offer a new direction for the design and multifunctional application of multiferroic materials.-T c low-dimensional monolayers but also offer a new direction for the design and multifunctional application of multiferroic materials.

Magnetoelectric (ME) coupling is highly desirable for sensors and memory devices. Herein, the polarization ( P ) and magnetization ( M ) of the DyFeO 3 single crystal were measured in pulsed magnetic fields, in which the ME behavior is modulated by multi-magnetic order parameters and has high magnetic-field sensitivity. Below the ordering temperature of the Dy 3+ -sublattice, when the magnetic field is along the c -axis, the P (corresponding to a large critical field of 3 T) is generated due to the exchange striction mechanism. Interestingly, when the magnetic field is in the ab -plane, ME coupling with smaller critical fields of 0.8 T ( a -axis) and 0.5 T ( b -axis) is triggered. We assume that the high magnetic-field sensitivity results from the combination of the magnetic anisotropy of the Dy 3+ spin and the exchange striction between the Fe 3+ and Dy 3+ spins. This work may help to search for single-phase multiferroic materials with high magnetic-field sensitivity.

Materials that coexist magnetic and electric properties on the molecular scale in single-molecule magnets (SMMs) with peculiar quantum behaviors have promise in molecular electronics and spintronics. Nevertheless, such molecular materials are limited in potentials because their magnetic signal cannot be transformed into an electrical signal through magnetoresistance or Hall effects for their high insulativity. The discovery of an entirely new material, ferroelectric SMMs (FE SMMs) is reported. This FE SMM also shows single-molecule magnetic behaviors, toroidal magnetic moments, and room-temperature ferroelectricity. The toroidal moment is formed by a vortex distribution of magnetic dipoles in triangular Dy 3 clusters. The analysis of ac magnetic susceptibility reveals the coexistence of three distinct magnetic relaxation processes at low temperatures. The ferroelectricity is introduced by incorporating polar alcohol molecules in the structure, which is confirmed by the X-ray diffraction and optical second harmonic generation (SHG) measurements. Moreover, the dielectric measurements reveal a ferroelectric-to-ferroelectric phase transition around 150 K due to the symmetry change from Pc to Pna2 1 . The coexistence of toroidal moment and ferroelectricity along with quantum magnetism in the rare-earth single-molecule magnets yields a unique class of multiferroics., (© 2022 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Inorganic-organic hybrid molecular multiferroic and magnetoelectric materials, similar to multiferroic oxide compounds, have recently attracted increasing attention because they exhibit diverse architectures, a flexible framework, fascinating physics, and potential magnetoelectric functionalities in novel multifunctional devices such as energy transformation devices, sensors, and information storage systems. Herein, the classification of multiferroicity and magnetoelectricity is briefly outlined and then the recent advances in the multiferroicity and magnetoelectricity of inorganic-organic hybrid molecular materials, particularly magnetoelectricity and the relevant magnetoelectric mechanisms and their categories are summarized. In addition, a personal perspective and an outlook are provided., (© 2021 Wiley-VCH GmbH.)

The stuffed tridymite structure Ba(Zn/Co) 1-x Si 1-x M 2x O 4 (M=Al 3+ and Fe 3+ ) is explored for the possible multiferroic behavior and to develop new inorganic colored materials. The compounds were synthesized by employing conventional solid-state chemistry methods in the temperature range 1100-1175 °C for 24 h. The powder X-ray diffraction (PXRD) and Rietveld refinement studies indicate that the compounds stabilize in the P63 space group (no. 173). The refinement results were also rationalized by employing Raman spectroscopic studies. The compounds were found to be second harmonic generation (SHG) active and show weak ferroelectric behavior. The co-substitution of Co 2+ and Fe 3+ in the structure gives rise to a weak ferromagnetic behavior to the compound, BaCo 0.75 Si 0.75 Fe 0.5 O 4 , making it a multiferroic material. The optical studies on the prepared compounds exhibited blue color (Co 2+ in T d geometry), purple color (Ni 2+ in T d geometry), and simultaneous substitution of Co 2+ and Fe 3+ gives rise to blue-green color owing to metal-to-metal charge transfer (MMCT) effect., (© 2020 Wiley-VCH GmbH.)

Room-temperature, long-range (300 nm), chirality-induced spin-selective electron conduction is found in chiral metal-organic Cu(II) phenylalanine crystals, using magnetic conductive-probe atomic force microscopy. These crystals are found to be also weakly ferromagnetic and ferroelectric. Notably, the observed ferromagnetism is thermally activated, so that the crystals are antiferromagnetic at low temperatures and become ferromagnetic above ∼50 K. Electron paramagnetic resonance measurements and density functional theory calculations suggest that these unusual magnetic properties result from indirect exchange interaction of the Cu(II) ions through the chiral lattice.

The present article is devoted to the characterization of the structural phase transitions of the [CH 3 NH 3 ][Co(COOH) 3 ] ( 1 ) perovskite-like metal-organic compound through variable-temperature single-crystal neutron diffraction. At room temperature, compound 1 crystallizes in the orthorhombic space group Pnma (phase I ). A decrease in temperature gives rise to a first phase transition from the space group Pnma to an incommensurate phase (phase II ) at approximately 128 K. At about 96 K, this incommensurate phase evolves into a second phase with a sharp change in the modulation vector (phase III ). At lower temperatures ( ca 78 K), the crystal structure again becomes commensurate and can be described in the monoclinic space group P 2 1 / n (phase IV ). Although phases I and IV have been reported previously [Boča et al. (2004). Acta Cryst. C 60 , m631-m633; Gómez-Aguirre et al. (2016). J. Am. Chem. Soc. 138 , 1122-1125; Mazzuca et al. (2018). Chem. Eur. J. 24 , 388-399], phases III and IV corresponding to the Pnma (00γ)0 s 0 space group have not yet been described. These phase transitions involve not only the occurrence of small distortions in the three-dimensional anionic [Co(HCOO) 3 ] - framework, but also the reorganization of the [CH 3 NH 3 ] + counter-ions in the cavities of the structure, which gives rise to an alteration of the hydrogen-bonded network, modifying the electrical properties of compound 1 .

Bismuth ferrite (BiFeO 3 ) is the most widely studied multiferroic material with robust ferroelectricity and antiferromagnetic ordering at room temperature. One of the possible device applications of this material is one that utilizes the ferroelectric/piezoelectric property itself such as ferroelectric memory components, actuators, and so on. Other applications are more challenging and make full use of its multiferroic property to realize novel spintronics and magnetic memory devices, which can be addressed electrically as well as magnetically. This progress report summarizes the recent attempt to control the piezoelectric and magnetic properties of BiFeO 3 by cobalt substitution., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The characterization of the crystal structure, phase transitions, magnetic structure and dielectric properties has been carried out on [CH 3 NH 3 ][Co(COOH) 3 ] (1) perovskite-like metal-organic compound through variable-temperature single-crystal and powder neutron and X-ray diffraction and relative permittivity measurements. The paraelectric to antiferroelectric-like phase transition observed at around 90 K is triggered by a structural phase transition; the structural studies show a change from Pnma space group at RT (1A) to P2 1 /n space group at low temperature (1B). This phase transition involves the occurrence of small distortions in the framework and counterions. Neutron diffraction studies have shown a magnetic order showing spontaneous magnetization below 15 K, due to the occurrence of a non-collinear antiferromagnetic structure with a weak ferromagnetic component, mainly due to the single-ion anisotropy of the Co II ions., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The broken symmetry along with anomalous defect structures and charging conditions at multiferroics surface can alter both crystal structures and electronic configurations, bringing in emergent physical properties. Extraordinary surface states are induced into original mutually coupled order parameters in such strongly correlated oxides, which flourish in diverse properties but remain less explored. Here, we report the peculiar surface ferroelectric states and reconfigurable functionalities driven by the relaxation of surface and consequent changes in O 2p and Y 4d orbital (p-d) hybridization within a representative hexagonal multiferroics, YMnO 3 . An unprecedented surface reconstruction is achieved by tailored p-d hybridization coupling with in-plane oxygen vacancies, which is atomically revealed on the basis of the advantages of state-of-the-art aberration-corrected (scanning) transmission electron microscopy. Further ab initio density functional theory calculations verify the key roles of in-plane oxygen vacancies in modulating polarization properties and electronic structure, which should be regarded as the atomic multiferroic element. This surface configuration is found to induce tunable functionalities, such as surface ferromagnetism and conductivity. Meanwhile, the controversial origin of improper ferroelectricity that is unexpectedly free from critical size has also been atomically unraveled. Our findings provide new insights into the design and implementation of surface chemistry devices by simply controlling the oxygen stoichiometry, greatly advance our understandings of surface science in strongly correlated oxides, and enable exciting innovations and new technological functionality paradigms.

Based on precursor powders with a size of 200-300 nm prepared by the low-temperature solid-state reaction method, phase-pure YMnO₃ ceramics are fabricated using spark plasma sintering (SPS). X-ray diffraction (XRD) and scanning electron microscopy (SEM) reveal that the high-purity YMnO₃ ceramics can be prepared by SPS at 1000 °C for 5 minutes with annealing at 800 °C for 2 h. The relative density of the sample is as high as 97%, which is much higher than those of the samples sintered by other methods. The present dielectric and magnetic properties are much better than those of the samples fabricated by conventional methods and SPS with ball-milling precursors, and the ferroelectric loops at room temperature can be detected. These findings indicate that the YMnO₃ ceramics prepared by the low temperature solid reaction method and SPS possess excellent dielectric lossy ferroelectric properties at room temperature, and magnetic properties at low temperature (10 K), making them suitable for potential multiferroic applications., Competing Interests: The authors declare no conflict of interest.

Based on precursor powders with a size of 200-300 nm prepared by the low-temperature solid reaction method, phase-pure YFeO₃ ceramics are fabricated using spark plasma sintering (SPS) at different temperatures. X-ray diffraction (XRD) and scanning electron microscopy (SEM) reveal that the high-purity YFeO₃ ceramics can be prepared using SPS, while the results from X-ray photoelectron spectroscopy (XPS) show that the concentration of oxygen vacancies resulting from transformation from Fe 3+ to Fe 2+ is low. The relative density of the 1000 °C-sintered sample is as high as 97.7%, which is much higher than those of the samples sintered at other temperatures. The present dielectric and magnetic properties are much better than those of the samples fabricated by conventional methods. These findings indicate that the YFeO₃ ceramics prepared by the low temperature solid reaction and SPS methods possess excellent dielectric and magnetic properties, making them suitable for potential applications involving magnetic storage.

The coexistence and coupling of ferromagnetic and ferroelectric orders in a single material is crucial for realizing next-generation multifunctional applications. The coexistence of such orders is confirmed at room temperature in epitaxial thin films of BiFe 1- x Co x O 3 (x ≤ 0.15), which manifests a spin structure change from a low-temperature cycloidal one to a high-temperature collinear one with canted ferromagnetism., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The hexagonal RMnO3(h-RMnO3) are multiferroic materials, which exhibit the coexistence of a magnetic order and ferroelectricity. Their distinction is in their geometry that both results in an unusual mechanism to break inversion symmetry and also produces a two-dimensional triangular lattice of Mn spins, which is subject to geometrical magnetic frustration due to the antiferromagnetic interactions between nearest-neighbor Mn ions. This unique combination makes the h-RMnO3 a model system to test ideas of spin-lattice coupling, particularly when both the improper ferroelectricity and the Mn trimerization that appears to determine the symmetry of the magnetic structure arise from the same structure distortion. In this review we demonstrate how the use of both neutron and X-ray diffraction and inelastic neutron scattering techniques have been essential to paint this comprehensive and coherent picture of h-RMnO3.

Some comments on the review by Sim et al. [(2016). Acta Cryst. B72, 3-19] are given. The review is devoted to hexagonal multiferroics RMnO3, in which there are ferroelectric and magnetic orders. Strong interaction between these orders causes a series of interesting properties of multiferroics.

A polarization-mediated heterointerface is designed to research the thermal stability of magnetic metal/oxide interfaces. Using polarization engineering, the thermal stability of the interface between BiFeO3 and CoFeB can be improved by about 100°C. This finding provides new insight into the chemistry of the metal/oxide heterointerface., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Multiferroic heterostructures consisting of Pb(Zr0·52Ti0·48)O3 and Fe0.7Ga0.3 thin films are integrated on microfabricated Si cantilevers, and they are operated in a non-linear regime. Enhanced mechanical coupling at the multiferroic interface and tunability of the resonant frequency are used to devise bistable dynamic states that can be reversibly switched by both DC magnetic and electric fields., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)