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Flexible quantum spin electronic devices based on ferromagnetic insulators have attracted wide attention due to their outstanding advantages of low-power dissipation and noncontact sensing. However, ferromagnetic insulators, such as monocrystalline yttrium iron garnet (Y3Fe5O12, YIG), hve weak stress effects with a small magnetostrictive coefficient (λ110, 10 ppm), making it difficult to achieve a large magnetic tunable amplitude. In this paper, large-scale (with a diameter of 40 mm), flexible Pt/YIG heterojunctions were obtained by double-cavity magnetron sputtering technology, indicating typical soft magnetism and good bending fatigue characteristics. Here, the 3 nm thickness of the Pt layer triggers an obvious magnetic proximity effect, in which the in-plane ferromagnetic resonance field is decreased by 70 Oe compared to flexible Cu/YIG heterojunctions. Meanwhile, it shows a wide tunable amplitude of 110 Oe under the flexible bending stresses, which is induced by the sensitive interface effect of Pt (3 nm)/YIG heterojunctions. The saturation magnetization of Pt/YIG heterojunctions is negatively correlated with Pt thickness rather than the relative stability of Cu/YIG heterojunctions, depending on the magnetic proximity effect. It brings greater application possibilities for flexible stress-sensitive magnetic oxides in spin logic electronic devices.

Control of magnetic anisotropy in thin films with perpendicular magnetic anisotropy is of paramount importance for the development of spintronics with ultralow-energy consumption and high density. Traditional magnetoelectric heterostructures utilized the synergistic effect of piezoelectricity and magnetostriction to realize the electric field control of magnetic anisotropy, resulting in additional fabrication and modulation processes and a complicated device architecture. Here, we have systematically investigated the electric current tuning of the magnetic properties of the metallic NiCo2O4film with intrinsic perpendicular magnetic anisotropy. Ferrimagnetic-to-paramagnetic phase transition has been induced through Joule heating, resulting in a rapid decrease of both magnetic coercivity and moment. An ultralow current density of 2.5 × 104A/cm2, which is 2 to 3 orders magnitude lower than that of conventional spin transfer torque devices, has been verified to be effective for the control of the magnetic anisotropy of NiCo2O4. Successful triggering of magnetic switching has been realized through the application of a current pulse. These findings provide new perspectives toward the electric control of magnetic anisotropy and design of spintronics with an ultralow driving current density.

Heat-assisted magnetic anisotropy engineering has been successfully used in selective magnetic writing and microwave amplification due to a large interfacial thermal resistance between the MgO barrier and the adjacent ferromagnetic layers. However, in spin–orbit torque devices, the writing current does not flow through the tunnel barrier, resulting in a negligible heating effect due to efficient heat dissipation. Here, we report a dramatically reduced switching current density of ∼2.59 MA/cm2in flexible spin–orbit torque heterostructures, indicating a 98% decrease in writing energy consumption compared with that on a silicon substrate. The reduced driving current density is enabled by the dramatically decreased magnetic anisotropy due to Joule dissipation and the lower thermal conductivity of the flexible substrate. The large magnetic anisotropy could be fully recovered after the impulse, indicating retained high stability. These results pave the way for flexible spintronics with the otherwise incompatible advantages of low power consumption and high stability.

The linearity of tunneling magnetoresistance (TMR) sensors is challenging due to the intrinsic magnetic hysteresis of the ferromagnetic Co-Fe-B layer used as the free layer. In this work, by using a composite free layer of Co-Fe-B/Ta/Co-Fe-Si-B with optimized geometric, we demonstrate vortex magnetic states in TMR sensors with large magnetic tunneling junctions, leading to low hysteresis and high stability under external magnetic fields, with a sensitivity of 6 mV/V/Oe (0.6% Oe $^{-{1}}$ ) and a nonlinearity below 0.5% FS within ±20 Oe. TMR vortex sensors with a composite free layer could be potentially useful in high precision current sensing in harsh environment.

In this study, a negative feedback mechanism was implemented in a noncontact voltage sensor to enhance its resistance to external interference. The noncontact sensor relies on capacitance coupling in space between the sensor probe and the power line being measured. However, this configuration leaves the sensor vulnerable to interference caused by environmental changes. The negative feedback mechanism was found to significantly improve the anti-interference properties of the sensor. The sensor exhibited stable voltage sensitivity at 50 Hz, operating within a voltage range of 800 V, with a nonlinearity of less than 1% between 100 and 800 V. In addition, the −3-dB frequency bandwidth of the sensor spanned a range from 10 Hz to 10 kHz, representing a significant improvement over sensors without the feedback design. This compact noncontact voltage sensor, equipped with a feedback structure, holds great potential for applications within distributed sensor networks in smart grids.

Very low frequency (VLF, 3–30 kHz) electromagnetic (EM) waves are widely used in areas such as mining, underwater communications, etc., because of their relatively large skin depth that enables long-distance propagation in a lossy medium. Mechanical antennas driven by acoustic oscillation or external mechanical movements have been proven to be promising candidates for low-frequency (LF) transmitters. Unfortunately, the mechanical relaxation in modulation caused by the motion inertia of mechanical antennas limits modulation rates. Here, we developed a high-rate active phase modulation (APM) scheme that can eliminate the mechanical relaxation and approach the theoretical maximal bit rate in a magnetoelectric (ME) antenna. The proposed ME antenna is based on a three-layered acoustic resonator with a length of only 8 cm and a total efficiency of $3.59\times 10^{-14}$ , which is closer to Chu’s limit. The proposed APM is realized by the 180° phase reversal of the bias magnetic field provided by a modulating coil. The high bit rate of 18 kbps at the resonant frequency of 27.75 kHz is demonstrated by using APM, one order of magnitude higher than that of passive phase modulation (PPM) due to the effective suppression of mechanical relaxation in such 180° phase variation.

A magnetoelectric (ME) sensor of face-shear type is demonstrated based on the ME composite consisting of (PbMg $_{{0}.{33}}$ Nb{0}.{67}O{3}}{)}_{{1}-{x}-(PbTiO $_{{3}}{)}_{x}$ piezoelectric single crystal (abbreviated as PMN-PT) and Metglas amorphous alloy. The face-shear strain is induced in PMN-PT via the magnetostriction of Metglas under a magnetic field, which generates an ME voltage through the ${d}_{{36}}$ piezoelectric coefficient. The proposed sensor reveals a high ME coupling coefficient of 48.8 V/cm Oe at resonant frequency ( $\sim $ 107.5 kHz), which is self-biased with the capability to detect ac magnetic fields of 4.58 nT at 1 kHz and 10.43 pT at resonant frequency, respectively. The self-biased face-shear mode ME sensor exhibits great potential for weak magnetic field detection.

Accurately measuring weak electric currents in the order of microamperes in a noninvasive manner is crucial yet challenging for industrial electronics. In this work, we first fabricated low-noise magnetic field sensor chips based on the tunneling magnetoresistive (TMR) effect. A composite free layer and a three-step annealing process were used to improve the performance, resulting in a sensitivity of 30 V/V/T (3 mV/V/Oe), nonlinearity below 0.5%, and reduction of the noise density from $1.4~\mu \text{V}$ /V/ $\surd $ Hz to $0.7~\mu \text{V}$ /V/ $\surd $ Hz at 1 Hz, in comparison with the traditional two-step annealing process. We then developed a weak-current sensing module with a differential design using two TMR sensor chips arranged antiparallelly. Equipped with a magnetic flux concentration structure and a low-noise signal processing circuit, we demonstrated transient measurement of weak current well below 1 mA with a wide bandwidth of dc-to-16 kHz, a dynamic range of ±150 mA (51 dB), and a rapid response time of $\sim 30~\mu \text{s}$ . The limit-of-detection (LoD) of the sensing module for dc and ac current reached 800 and $300~\mu \text{A}$ (rms), respectively, which is about 30% lower than the single-chip design. This weak-current sensor based on differential TMR has the potential to be useful for industrial applications in smart grids and green energy.

Finding an efficient way for underwater communication with a portable antenna at very low frequency (VLF 3–30 kHz) is challenging since the conventional electrical antennas require the size to be larger than 1/10 of the wavelength. Recently, acoustically driven antennas were proposed to realize portable VLF communication in air but lack the demonstration in a lossy environment. Here, we reported the first VLF underwater communication system based on a pair of acoustically actuated magnetoelectric (ME) antennas with small size of 10 cm in length. A theoretical analysis of reflection and radiation performance of the ME antenna was conducted, where the electromechanical resonance (EMR) frequency and effective magnetic dipole moment were estimated, and a near-field coupling model of a pair of ME antennas was further established. The results of theoretical predictions and finite element model (FEM) simulations were then compared with experimental measurements and their differences were discussed. A prototype of underwater communication system based on the ME antenna pair was finally presented, where a binary digital modulation with a bit rate of 100 b/s has been demonstrated, confirming the feasibility of ME antennas for portable underwater communication.

Magnetoelectric (ME) sensors based on piezoelectric/ferromagnetic composites have been investigated extensively due to their resonance-enhanced ME coupling effect and high sensitivity for magnetic field, especially at resonant frequency. However, the sensitivity drops rapidly when the frequency drifts away from resonance, making it unsuitable for low-frequency applications. Frequency modulation has been proposed as an effective method to up-convert the frequency of the desired signal into the mechanical resonance. In this work, we study the optimized amplitude and frequency of the modulation field, which improve the sensitivity at low frequency by two orders of magnitude without increasing the noise level. Magnetic field of 200 pT is detected at 10 Hz with a near-flat frequency response in the range of 1–100 Hz, showing promising potential for low-frequency applications in smart grid and renewable energy.

Abstract: Manipulating strain mode and degree that can be applied to epitaxial complex oxide thin films have been a cornerstone of strain engineering. In recent years, lift-off and transfer technology of the epitaxial oxide thin films have been developed that enabled the integration of heterostructures without the limitation of material types and crystal orientations. Moreover, twisted integration would provide a more interesting strategy in artificial magnetoelectric heterostructures. A specific twist angle between the ferroelectric and ferromagnetic oxide layers corresponds to the distinct strain regulation modes in the magnetoelectric coupling process, which could provide some insight in to the physical phenomena. In this work, the La0.67Sr0.33MnO3(001)/0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3(011) (LSMO/PMN-PT) heterostructures with 45º and 0º twist angles were assembled via water-etching and transfer process. The transferred LSMO films exhibit a fourfold magnetic anisotropy with easy axis along LSMO < 110 >. A coexistence of uniaxial and fourfold magnetic anisotropy with LSMO [110] easy axis is observed for the 45° Sample by applying a 7.2 kV cm−1electrical field, significantly different from a uniaxial anisotropy with LSMO [100] easy axis for the 0° Sample. The fitting of the ferromagnetic resonance field reveals that the strain coupling generated by the 45° twist angle causes different lattice distortion of LSMO, thereby enhancing both the fourfold and uniaxial anisotropy. This work confirms the twisting degrees of freedom for magnetoelectric coupling and opens opportunities for fabricating artificial magnetoelectric heterostructures.

Electric field (E-field) control of magnetism based on magnetoelectric coupling is one of the promising approaches for manipulating the magnetization with low power consumption. The evolution of magnetic domains under in-situE-fields is significant for the practical applications in integrated micro/nano devices. Here, we report the vector analysis of the E-field-driven antiparallel magnetic domain evolution in FeCoSiB/PMN-PT(011) multiferroic heterostructures via in-situquantitative magneto-optical Kerr microscope. It is demonstrated that the magnetic domains can be switched to both the 0° and 180° easy directions at the same time by E-fields, resulting in antiparallel magnetization distribution in ferromagnetic/ferroelectric heterostructures. This antiparallel magnetic domain evolution is attributed to energy minimization with the uniaxial strains by E-fields which can induce the rotation of domains no more than 90°. Moreover, domains can be driven along only one or both easy axis directions by reasonably selecting the initial magnetic domain distribution. The vector analysis of magnetic domain evolution can provide visual insights into the strain-mediated magnetoelectric effect, and promote the fundamental understanding of electrical regulation of magnetism.

Piezoelectric ceramics exhibit three conventional piezoelectric coefficients, i.e., d33, d31, d15, due to their ∞mmcrystal symmetry. Unconventional piezoelectric coefficients, such as d11, d12, d13, d14, d16, etc., can only be extracted from piezoelectric single crystals of special symmetry with specific cut direction. Here we demonstrate a rotated poling method to realize unconventional piezoelectric coefficients in perovskite piezoelectric ceramics. This method is elaborated in theory and experimentally proven to be effective. Full nonzero piezoelectric coefficients in the 3 × 6 piezoelectric coefficients matrix can be obtained by combining these “quasi (effective) piezoelectric coefficients” with the conventional piezoelectric coefficients, which would expand applications in a wide variety of piezoelectric devices.

Exchange bias between ferromagnetic and antiferromagnetic layers has been widely utilized in spintronic devices. Controlling the exchange bias in magnetic multilayers by an electric field (E-field) has been proposed as a low-power solution for manipulating the macroscopic properties such as exchange bias fields and magnetization values, while how the magnetic domains respond to the E-fields has rarely been reported in an exchange-biased system. Here, we realize the vector imaging of reversible electrical modulation of magnetization reversal in exchange-biased CoFeB/IrMn/PMN-PT (011) multiferroic heterostructures, utilizing in-situquantitative magneto-optical Kerr effect (MOKE) microscopy. Under the electrical control, magnetic domains at −80 Oe rotate reversibly between around 160° and 80°–120°, whose transverse components reverse from 225° to 45° correspondingly. Moreover, pixel-by-pixel comparisons are conducted to further imply the reversible magnetization reversal by E-fields. E-field-induced reversible magnetization reversal is also demonstrated without applying external magnetic fields. Vector imaging of electrical manipulation of exchange bias is of great significance in understanding the magnetoelectric effect and the development of next-generation spintronic devices.

Since the rise of two-dimensional (2D) semiconductors, it seems that electronic devices will soon be upgraded with spintronics, in which the manipulation of spin degree of freedom endows it obvious advantages over conventional charge-based electronics. However, as the most crucial prerequisite for the above-mentioned expectation, 2D semiconductors with adjustable magnetic interaction are still rare, which has greatly hampered the promotion of spintronics. Recently, transition metal phosphates have attracted tremendous interest due to their intrinsic antiferromagnetism and potential applications in spintronics. In the work described herein, parasitic ferromagnetism is achieved for the first time by exfoliating an antiferromagnetic chalcogenophosphate to a few layers. Taking the transition metal chalcogenophosphate Mn2P2S6as an example, the antiferromagnetic transition at the Néel temperature is completely suppressed, and the magnetic behaviors of the as-obtained few-layered Mn2P2S6are dominated by parasitic ferromagnetism. We experimentally verify an electron redistribution by which part of the Mn 3d electrons migrate and redistribute on P atoms in few-layered Mn2P2S6due to the introduced Mn vacancies. The results demonstrated here broaden the tunability of the material’s magnetic properties and open up a new strategy to rationally design the magnetic behaviors of 2D semiconductors, which could accelerate the applications of spintronics.

The operation mechanism of giant magnetoresistance (GMR) sensors relies on the linear response of the magnetization direction to an external magnetic field. Since the magnetic anisotropy of ferromagnetic layers can be manipulated by a strain-mediated magnetoelectric coupling effect, we propose a tunable GMR magnetic field sensor design that allows for voltage tuning of the linear range and sensitivity. A spin valve structure Ru/CoFe/Cu/CoFe/IrMn/Ru is grown on a PMN-PT (011) substrate, and the magnetization directions of ferromagnetic layers can be controlled by an electric field. An adjustable linear magnetoresistance is therefore induced. Based on the magnetoelectric coupling effect and spin valve, we prepared tunable GMR magnetic field sensors with bridge structures. The linear sensing range of a DC magnetic field is enhanced 6 times by applying an electric field of 14 kV/cm. The electrically tunable GMR sensor fulfills the requirements to work at different magnetic field ranges in the same configuration, therefore exhibiting great potential for applications in the Internet of things.

The tunable range of RF/microwave devices is limited not only due to the difficulty in growing high-quality magnetic oxide thin films but also because of their low magnetostrictive coefficient as in Y3Fe5O12(YIG) thin films. In this work, we have fabricated flexible YIG thin films by using pulsed laser deposition (PLD) technology, which exhibit a low-damping constant (2.67 × 10−4) and well-established magnetic properties suitable for RF/microwave materials. A noticeable ferromagnetic resonance (FMR) field shift of 180 Oe was obtained along the out-of-plane direction viaa flexible tunable factor f(R), which results in a frequency shift as high as 550 MHz. The result shows a greater FMR tuning than that induced by ferroelectric single crystals. At the same time, a systematic theoretical framework for tuning FMR characteristics was presented for the flexible YIG/mica thin films, which would provide an effective tuning method for other flexible magnetic oxides with low magnetostrictive coefficients. Last but not least, a flexible coplanar waveguide (CPW) integrated with the flexible YIG thin films shows excellent microwave magnetic stability and fatigue-resistant behavior. It would open a new door for further applications, such as flexible spiral detectors and high-frequency signal processors in the near future.

Mechanical flexible electronic/spintronic devices have shown enormous application potential to impact our daily life. Here, an in situ low-voltage-controlled flexible field-effect transistor structure was exploited, which consists of a support layer (mica), functional layer (Fe3O4), and control layer (ionic gel). By applying a low voltage (1.5 V) on the ionic gel, the spin-dynamic properties of the function layer were manipulated and a reversible, nonvolatile 345 Oe ferromagnetic resonance field (Hr) shift was achieved, which corresponds to a large magnetoelectric (ME) coefficient of 230 Oe/V. In addition, a reversible 126 Oe Hrshift (84 Oe/V) was obtained when the layers were bent at curvature radius r= 15 mm. The ME tunability could be attributed to the E-field induced ionic transformation between Fe2+and Fe3+at the interface via electrostatic induction. This sandwich structure shows an excellent and effective ionic gel gating system and paves the way for low-voltage-tunable, nonvolatile, and flexible spintronic devices such as memory devices, sensors, and logical devices.

In spite of recent rapid development of flexible electronics, voltage-tunable spintronic structures and devices on flexible substrates have been rarely studied. Here, voltage control of magnetic anisotropy (VCMA) is demonstrated via ionic gel (IG) gating on flexible polyimide substrates with a circuit operating voltage of 1.8 V. A reversible, nonvolatile VCMA switching of 114 Oe is achieved in Pt/Fe/Pt multilayer, where the spatial magnetic anisotropy distribution is determined quantitatively by electron spin resonance technique. This IG gating process is repeatable as the substrates are under different bending conditions. The voltage modulation of magnetic anisotropy through IG gating with excellent flexibility proposes potential applications in low-power wearable spintronic devices.

The trend of mobile Internet requires portable and wearable devices as bio-device interfaces. Electric field control of magnetism is a promising approach to achieve compact, light-weight, and energy-efficient wearable devices. Within a flexible sandwich heterostructure, perpendicular magnetic anisotropy switching was achieved vialow-voltage gating control of an ionic gel in mica/Ta/(Pt/Co)x/Pt/ionic gel/Pt, where (Pt/Co)xacted as a functional layer. By conducting in situVSM, EPR, and MOKE measurements, a 1098 Oe magnetic anisotropy field change was determined at the bending state with tensile strain, corresponding to a magnetic anisotropy energy change of 3.16 × 105J/m3and a giant voltage tunability coefficient of 0.79 × 105J/m3·V. The low voltage and strain dual control of magnetism on mica substrates enables tunable flexible spintronic devices with an increased degree of manipulation.

Traditional magnetostrictive/piezoelectric laminated composites rely on the two-dimensional interface that transfers stress/strain to achieve the large magnetoelectric (ME) coupling, nevertheless, they suffer from the theoretical limitation of the strain effect and of the substrate clamping effect in real ME applications. In this work, 3D NZFO/BTO-pillar nanocomposite films were grown on SrTiO3by template-assisted pulsed laser deposition, where BaTiO3(BTO) nanopillars appeared in an array with distinct phase transitions as the cores were covered by NiZn ferrite (NZFO) layer. The perfect 3D heteroepitaxial interface between BTO and NZFO phases can be identified without any edge dislocations, which allows effective strain transfer at the 3D interface. The 3D structure nanocomposites enable the strong two magnon scattering (TMS) effect that enhances ME coupling at the interface and reduces the clamping effect by strain relaxation. Thereby, a large FMR field shift of 1866 Oe in NZFO/BTO-pillar nanocomposite was obtained at the TMS critical angle near the BTO nanopillars phase transition of 255 K.

The ongoing demand for efficient and low-energy consumption spintronic devices has motivated the idea of manipulating magnetism by ionic liquid (IL) electrolyte gating at low voltages. Although magnetoelectric (ME) coupling has already been realized in some field-effect-transistor (FET) structures, some vital parameters such as giant ME coupling coefficient, excellent reversibility and low gating voltage seldom come at the same time, which greatly suppresses industrialization. Here we demonstrate a large 552 Oe spin dynamics modulation of Fe3O4thin films induced at a gating voltage of Vg= +1.5 V in an IL-gated Au/[DEME]+[TFSI]−/Fe3O4/MgO heterostructure with good reversibility up to 80 cycles, giving rise to a high ME coefficient of 368 Oe V−1. Such a large ME tunability under low Vgcould be attributed to the electric field (E-field) induced ionic transformation between Fe2+and Fe3+at the interface. The tiny thickness change (∼2 angstrom) and roughness change of Fe3O4films under Vg= +1.5 V illustrated by in situX-ray reflection (XRR) give a reasonable explanation of the outstanding reversible property. Interestingly, it is found that the Verwey transition temperature of Fe3O4has a strong dependence on Vg, revealing the potential of IL gating control of the intrinsic spin ordering inside magnetic films. This work drives forward the low-voltage induced reversible ME coupling to high-performance spintronic devices.

Controlling spin dynamics through modulation of spin interactions in a fast, compact, and energy-efficient way is compelling for its abundant physical phenomena and great application potential in next-generation voltage controllable spintronic devices. In this work, we report electric field manipulation of spin dynamicsthe two-magnon scattering (TMS) effect in Ni0.5Zn0.5Fe2O4(NZFO)/Pb(Mg2/3Nb1/3)–PbTiO3(PMN–PT) multiferroic heterostructures, which breaks the bottleneck of magnetostatic interaction-based magnetoelectric (ME) coupling in multiferroics. An alternative approach allowing spin-wave damping to be controlled by external electric field accompanied by a significant enhancement of the ME effect has been demonstrated. A two-way modulation of the TMS effect with a large magnetic anisotropy change up to 688 Oe has been obtained, referring to a 24 times ME effect enhancement at the TMS critical angle at room temperature. Furthermore, the anisotropic spin-freezing behaviors of NZFO were first determined via identifying the spatial magnetic anisotropy fluctuations. A large spin-freezing temperature change of 160 K induced by the external electric field was precisely determined by electron spin resonance.

Electric field control of dynamic spin interactions is promising to break through the limitation of the magnetostatic interaction based magnetoelectric (ME) effect. In this work, electric field control of the two-magnon scattering (TMS) effect excited by in-plane lattice rotation has been demonstrated in a La0.7Sr0.3MnO3(LSMO)/Pb(Mn2/3Nb1/3)-PbTiO3(PMN-PT) (011) multiferroic heterostructure. Compared with the conventional strain-mediated ME effect, a giant enhancement of ME effect up to 950% at the TMS critical angle is precisely determined by angular resolution of the ferromagnetic resonance (FMR) measurement. Particularly, a large electric field modulation of magnetic anisotropy (464 Oe) and FMR line width (401 Oe) is achieved at 173 K. The electric-field-controllable TMS effect and its correlated ME effect have been explained by electric field modulation of the planar spin interactions triggered by spin–lattice coupling. The enhancement of the ME effect at various temperatures and spin dynamics control are promising paradigms for next-generation voltage-tunable spintronic devices.

Yttrium iron garnet (YIG) is of great importance in RF/microwave devices for its low loss, low intrinsic damping, and high permeability. Nevertheless, tuning of YIG-based multiferroics is still a challenge due to its near-zero magnetostriction and the difficulty of building epitaxial interface between ferromagnetic garnet and ferroelectric perovskite phases. In this work, the vertically aligned heterostructure of YIG:BTO/STO(001) with local epitaxial interface between BTO and YIG is well-constructed, where the single crystal BTO pillars are embedded in YIG matrix. A large magnetoelectric coupling effect that drives YIG’s FMR shift up to 512 and 333 Oe (1–2 order greater than those of all state-of-the-art progresses) is obtained through BTO ferroelectric phase changes induced by temperature variation at 295 and 193 K, correspondingly. This record high magnetoelectric tunability of YIG paves a way toward thermal/electrical tunable YIG devices.

Magnetoelectric coupling properties are limited to the substrate clamping effect in traditional ferroelectric/ferromagnetic heterostructures. Here, Fe3O4/BaTiO3nanopillar composites are successfully constructed. The well-ordered BaTiO3nanopillar arrays are prepared through template-assisted pulsed laser deposition. The Fe3O4layer is coated on BaTiO3nanopillar arrays by atomic layer deposition. The nanopillar arrays and heterostructure are confirmed by scanning electron microscopy and transmission electron microscopy. A large thermally driven magnetoelectric coupling coefficient of 395 Oe °C–1near the phase transition of BaTiO3(orthorhombic to rhombohedral) is obtained, indicating a strong strain-induced magnetoelectric coupling effect. The enhanced magnetoelectric coupling effect originated from the reduced substrate clamping effect and increased the interface area in nanopillar structures. This work opens a door toward cutting-edge potential applications in spintronic devices.

Permalloy with low ferromagnetic resonance linewidth has great application potential in spintronic/microwave devices. In this work, we demonstrated that the nonmagnetic (Cu) layer’s sputtering rate has a considerable impact on Ni0.81Fe0.19’s linewidth in Cu (4 nm)/Ni0.81Fe0.19(3 nm) bilayer heterostructures. A monotonically decreasing out-of-plane linewidth was displayed as the sputtering rates increased from 0.27 to 1.75 Å/s due to interdiffusion. Meanwhile, a large reduction of the in-plane linewidth from 18.54 to 7.83 mT was also obtained from suppressing the interfacial inhomogeneity and two-magnon scattering effects. The present work contributes to a clearer understanding of Cu/Ni0.81Fe0.19nanoscale films’ interfacial inhomogeneity and opens a new road on tailoring magnetodynamic properties.