ME Coupling Research Articles

Effects of Ni2+ doping on magnetic and magnetoelectric properties of Y-type hexaferrite BaSrCo2Fe11AlO22

Magnetoelectric hexaferrites are the promising candidate materials for low-consumption magnetic memory device application, due to the existence of room-temperature magnetoelectric effect and the tunable magnetic structure. In this work, we studied the Ni doping effect on a rare room-temperature multiferroic BaSrCo2Fe11AlO22. With the comprehensive study of magnetism, magnetoelectricity, and ferroelectric properties, magnetoelectric phase diagrams of BaSrCo2-xNixFe11AlO22 were established. Generally, Ni doping has two important effects on magnetic and magnetoelectric properties. One is to strengthen superexchange interactions, greatly enhancing magnetic order temperature. Another effect is to destabilize the noncollinear magnetic structure at high temperature, causing the absence of ME effect at room temperature. In addition, the converse ME effects have been studied, revealing that converse ME coupling strength become weakened with the increase in Ni concentration. Our systematic studies provide important clues for synthesizing high performance magnetoelectric hexaferrites.

Enhancement of magnetoelectric coupling in laminate composites of textured Fe–Ga thin sheet and PZT

Magneto-mechano-electric (MME) generators consisting of piezoelectric and magnetostrictive materials can convert the stray magnetic noise to useful electric energy for the wireless sensor networks utilizing the magnetoelectric coupling effect and magnetic interactions. In this paper, a scalable engineering approach was proposed to fabricate the laminate MME generator composed of a PZT/Fe–Ga/PZT sandwich structure. The Goss-oriented Fe81Ga19 thin sheet with a large magnetostriction of 244 ppm was produced by a simple and low-cost approach, and the commercial polycrystalline piezoelectric ceramic products (PZT-5H) were used as the PZT layers. The effect of grain orientation, device structure, magnetic field amplitude, and resonance frequency on the electrical output of the PZT/Fe–Ga/PZT MME generator was investigated. The electrical output of the MME generator containing the Goss-oriented Fe81Ga19 thin sheet reached an AC voltage of 4.58 V and the ME coefficient of 76.33 V/cm·Oe under a low excitation magnetic field of 26 Oe at a low resonance frequency of 26 Hz. The MME generator with a Goss-oriented Fe–Ga layer shows 4.7 times higher output voltage and ME coupling coefficient than that with the no-oriented polycrystalline Fe–Ga layer, but only 81% of the latter’s resonance frequency. This is related to the significant increase in magnetostriction due to the texture transition after secondary recrystallization annealing at the temperature of 950 °C. This paper provides a very promising solution to meet the self-power supply needs of the Internet of Things utilizing low-value and low-frequency magnetic fields.

Establishment of magneto-electric response in GdFeO3 doped PbTiO3 solid solutions

This work promotes a thorough examination of the magnetic impact on the multiferroicity of the sample. The usual solid-state reaction method was used to synthesis Pb1-xGdxTi1-xFexO3 with x = 0.21, 0.22, and 0.23. XRD analysis showed a pure homogeneous single-phase compound with a tetragonal structure, indicating perfect diffusivity of Gd atoms into the PbTiO3 lattice. All of the samples show clear grain growth between 7.8 and 10.5 μm in the SEM images, proving that they were sintered at the correct temperature. Furthermore, ferroelectric transition temperature reduces from 388 K to below the ambient temperature range as the doping value of Gd grows. The room temperature P-E hysteresis loops indicated that the remnant polarization of the sample drops from 8.66 μC/cm2 to 2.065 μC/cm2 for x = 0.21 to 0.23 sample. Three distinct phenomena supported the ME coupling of all samples. The sample x = 0.21 exhibits the maximum magneto-dielectric response of 2.2 % at 1.2T having highest MDR coupling coefficient value of −1.41g2/emu2. Moreover, the sample x = 0.21 shows the highest shift in magnetization before and after electric poling of about 0.105 emu/g. As a result, the sample x = 0.21 emerges as a viable choice for application in a variety of multifunctional devices.

Tuning magnetoelectric effect in Bi6Fe1.6Co0.2Ni0.2Ti3O18/La0.7Sr0.3MnO3/Bi6Fe1.6Co0.2Ni0.2Ti3O18 sandwich films employing micromagnetic moments and force on dipole

Mutual modulating ferroelectric polarization and magnetization provides the potential for realizing new-type low-energy consumption, high-density memory, and logic processors. Despite extensive investigations, the underlying mechanism remains elusive. In this work, we employed Bi6Fe1.6Co0.2Ni0.2Ti3O18 (BFCNT) as the ferroelectric phase and La0.7Sr0.3MnO3 (LSMO) as the ferromagnetic phase to form environmentally friendly BFCNT/LSMO/BFCNT sandwich films fabricated on flexible FTO substrates using the all-solution chemical-solution deposition route. The ferromagnetism, ferroelectricity, and magnetoelectric coupling effect of the sandwich films were investigated by measuring at macro and micro scales. Then a dynamic micromagnetic moment model and a dipole force model were proposed to study the intermodulation of both ferromagnetism and ferroelectricity. It suggested that the combination of magnetic and electric moments makes the deflection of magnetization (or polarization) and a shift of the electron orbit, causing the movement of domain walls and the flip of magnetic domains, and thus a decrease of the saturation magnetization, offering new insights into the underlying physics of ME coupling in the model system.

Magnetoelectric multiferroic properties of BaTiO3-CoFe2O4-BaTiO3 tri-layer thin films fabricated by pulsed laser deposition

A magnetoelectric multiferroic bi-phase system with robust ferroelectric and ferro/ferri-magnetism response at room temperature would be ideally suitable for microelectronics, memory devices, and for spintronic applications. BaTiO3/CoFe2O4/BaTiO3(BTO/CFO/BTO) heterostructured films were pulsed laser deposition grown on Pt(111)/TiO2/SiO2/Si substrates. High quality polycrystalline films were grown by thermal annealing at 750 °C, at an oxygen partial pressure of 100 mTorr for 1 h. Crystal quality and phase formation information was monitored using X-ray diffraction (XRD). XRD confirm the growth of polycrystalline heterostructures and the coexistence of both perovskite BTO and spinel CFO phases in heterostructures. In order to obtain robust magnetoelectric coupling, we studied the tri-layer structure as a representative ferroelectric/ferrimagnetic/ferroelectric system. We report the ferroelectric, leakage current behavior, ferrimagnetic, and frequency dependent ME properties of the films. Ferroelectric BTO and ferrimagnetic inverse spinel CFO nature is also confirmed using the piezoresponse force microscopy and magnetic force microscopy measurements. These nanostructures exhibit high saturation polarization (Ps ∼ 99.86 µC/cm2), saturation magnetization (Ms ∼ 51.48 emu/cm3), and a strong ME coupling coefficient of ∼ 274 mV/cm-Oe with a bias magnetic field of + 90 Oe, anda frequency of 1 kHz revealing them as prospective candidates for multifunctional applications.

Alginate functionalized MFe2O4 (MNi, Co) nanoparticles and hydrated salt incorporated flexible PVDF ternary nanocomposite fibers for magnetoelectric applications

AbstractMagnetoelectric (ME) polymer nanocomposites find a wide range of applications as ME sensors, energy storage devices, magneto‐mechano‐electric nanogenerators, tissue engineering scaffolds, and so forth. Functionalizing ferrite fillers is an effective strategy to improve the ferrite‐polymer interaction and, thereby, the functional properties. In the present work, we developed ternary nanocomposite fibers of polyvinylidene fluoride loaded with hydrated salt and alginate functionalized ferrite nanoparticles. Nanocomposites with functionalized ferrite fillers were found to have better dielectric and ME properties. The highest values of dielectric constant (14.7) and ME coupling coefficient (18.2 mV cm−1 Oe−1) were obtained for ternary nanocomposite fiber with functionalized nickel ferrite nanoparticles. The present study opens new avenues for developing flexible ME nanocomposites for realizing flexible ME nanocomposites with the required properties for developing next‐generation devices for diverse applications.

Unravelling the linear and biquadratic magnetoelectric coupling in Ba0.95Sn0.05Ti0.95 Ga0.05O3 – CoFe1.8Ga0.2O4 particulate multiferroic composites

Since multiferroic composites have substantially stronger magnetoelectric coupling between the order parameters than the single-phase multiferroics, they are more interesting prospects for next-generation multi-state memories and spintronic devices. In light of this, the current work outlines the fabrication of ferroelectric perovskite BaTiO3 and ferrimagnetic spinel CoFe2O4-based particulate multiferroic composites with general formulla (1-x) Ba0.95Sn0.05Ti0.95 Ga0.05O3 – x CoFe1.8Ga0.2O4 (x = 0.04, 0.08 & 0.12). At room temperature, the gallium and tin doping enhanced the dielectric properties of BaTiO3 (ε ´ =9200), and particulate composite (ε ´ =6000) with 12% of CoFe1.8Ga0.2O4 phase. In the same composite, the reduced leakage current density of 3.4 μA/cm2 and improved magnetoelectric properties, with linear and quardatic coupling coefficients of 3.41 mVcm−1Oe−1 and 3.4 × 10−4 mVcm−1Oe−2 were achieved. In composites with a larger magnetic phase, the decrease in cell volume and increased tetragonality produces the compressive strain, that in turn improves the ME coupling. Diffused ferroelectric transitions were ascertained by using the Curie- Weiss Law. Enhanced dielectric properties are linked to decrease in hopping and bond lengths, caused by the incorporation of non-magnetic Ga3+ ions in the CoFe2O4 lattice. A reduction in leakage current density was observed on Sn doping. The calculated square-ness ratios reveal an ordered multi-domain structure. Improved dielectric response along with linear and biquadratic coupling makes these Sn and Ga doped BaTiO3-CoFe2O4 particulate composites as potential candidates for magnetoelectric devices.

Full Antiferroelectric Performance and GMR Effect in Multiferroic La0.75Ba0.25Fe12O19 Ceramic

The potential application of multiferroic materials in new electronic devices attracts more and more attention from people either in an academic field or industry. This paper reports that M-type lanthanum-doped barium ferrite (La0.75Ba0.25Fe12O19) demonstrates full antiferroelectric (AFE) and excellent magnetoelectric coupling effects at room temperature, while its AFE phase displays a zero macroscopic net polarization. The dramatic change in the dielectric constant near the Curie temperature far below room temperature represents the transition from ferroelectrics (FE) to antiferroelectrics. The fully separated double electric polarization hysteresis (P–E) loops confirmed its AFE performance. Its EF and EA are located at 1100 kV/cm and 850 kV/cm, respectively. The large M–H loop showed a strong magnetic property simultaneously. The UV-Vis-NIR optical spectrum revealed that La0.75Ba0.25Fe12O19 is also a semiconductor, whose direct bandgap energy (Eg) was determined to be 1.753 eV. Meanwhile, La0.75Ba0.25Fe12O19 showed strong ME coupling and a GMR effect. A 1.1 T magnetic field reduced its resistance by 110% at 30 kHz. The multiple functions combined in one phase would create new options for high energy storage capacitors, microactuators, pyroelectric safety sensors, cooling devices, and pulsed power generators and so on, as well as great opportunities for generating new electronic devices with active magnetoelectric coupling effects.

Magnetoelectric effect generated through electron transfer from organic radical to metal ion.

Magnetoelectric (ME) materials induced by electron transfer are extremely rare. Electron transfer in these materials invariably occurs between the metal ions. In contrast, ME properties induced by electron transfer from an organic radical to a metal ion have never been observed. Here, we report the ME coupling effect in a mononuclear molecule-based compound [(CH3)3NCH2CH2Br][Fe(Cl2An)2(H2O)2] (1) [Cl2An=chloranilate, (CH3)3NCH2CH2Br+ = (2-bromoethyl)trimethylammonium]. Investigation of the mechanism revealed that the ME coupling effect is realized through electron transfer from the Cl2An to the Fe ion. Measurement of the magnetodielectric (MD) coefficient of 1 indicated a positive MD of up to ∼12% at 103.0Hz and 370K, which is very different from that of ME materials with conventional electron transfer for which the MD is generally negative. Thus, the current work not only presents a novel ME coupling mechanism, but also opens a new route to the synthesis of ME coupling materials.

Strain‐Sensitive Flexible Magnetoelectric Ceramic Nanocomposites

AbstractMagnetoelectric (ME) oxide materials can convert magnetic input into electric output and vice versa, making them excellent candidates for advanced sensing, data storage, and communication. However, their application has been limited to rigid devices due to their brittle nature. Here, flexible ME oxide composite (BaTiO3/CoFe2O4) thin film nanostructures with distinct ME coupling coefficients are reported. In contrast to rigid bulk counterparts, these ceramic nanostructures display a flexible behavior after being released from the substrate, and can be transferred onto a stretchable substrate such as polydimethylsiloxane. These ceramic films possess high ME coefficients due to minimized clamping effect and preferred crystalline orientation, and exhibit reversibly tunable ME coupling via mechanical stretching thanks to their large elasticity (>4%). It is believed that the study can open up new avenues for integrating ceramic ME composites into micro‐/nanoelectromechanical system and soft robotic devices.

Electric field tuning of ferromagnetic resonance field and linewidth in epitaxial LiFe5O8/PMN-PT (0 1 1) heterostructure

Here a typical ME heterostructure is prepared by growing epitaxial LiFe5O8 (LFO) thin films on Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) (011) substrates by pulse laser deposition (PLD). Ferromagnetic resonance (FMR) test results at in situ voltage show that the tunability of FMR field (Hr) and linewidth (ΔH) have strong angular dependences with external magnetic field. It is inferred that the change of the orientation of equilibrium magnetization contributes to the abnormal enhancement of ME coupling at certain angles. The theoretical fitting reveals that the Gilbert damping (ΔHGilb), two-magnon scattering (ΔHTMS) and inhomogeneous broadening (ΔHinhom) play the different roles for the increase of linewidth of LFO film at various magnetic field directions. Additionally, the ME coupling in LFO/PMN-PT (011) heterostructure shows well temperature stability at range of 100–300 K. Those discoveries enrich the understanding of the ME phenomenon and provide guidance to the development of novel multiferroic materials and devices.

Enhancement of magnetoelectric coupling and anisotropy by Galfenol/PZT/Galfenol magnetoelectric sandwich device

In this work, we reported the large magnetoelectric coupling coefficient and magnetoelectric coupling anisotropy in Galfenol/PZT/Galfenol 2-2 symmetric magnetoelectric sandwich devices. The directional solidification method was used to produce a Galfenol alloy with <001> orientation, which possesses a significant magnetostriction of 279 ppm and a piezomagnetic coefficient of 14.8 ppm/Oe. A magnetoelectric coupling laminate of Galfenol/PZT/Galfenol was also prepared. The magnetoelectric coupling coefficient can reach 55.0 V/cm Oe at the resonance frequency under a 0.35 Oe AC excitation magnetic field due to the significant magnetostriction and high piezomagnetic coefficient. Furthermore, there was excellent linearity and sensitivity between the magnetoelectric output voltage and the AC excitation magnetic field. Simultaneously, the device displayed in-plane magnetoelectric anisotropy and cosine variation as the magnetic field angle changed. At its resonance frequency, the device produced a maximum power of 1.4 mW. Finally, the device was shown to power 42 LEDs and a temperature/humidity sensor, demonstrating that the device withGalfenol/PZT/Galfenol sandwich structure has potential in magnetic field sensing and energy harvesting applications. • The device presented the in-plane anisotropy of ME coupling and cosine variation with the change of magnetic field angle. • The produced maximum power of the device was successfully demonstrated to power 42 LEDs and temperature/humidity sensors at its resonance frequency.

Magnetically Tuned Impedance and Capacitance for FeGa/PZT Bilayer Composite under Bending and Longitudinal Vibration Modes

A magnetically tunable magnetoelectric transducer consisting of rectangular Fe82Ga18(FeGa)/Pb(Zr,Ti)O3(PZT) composites is developed, and their magnetoimpedance and magnetocapacitance effects are investigated under bending and longitudinal modes. Specifically, the composites' impedance and capacitance are found to vary with dc magnetic field Hdc, which results from the varied effective dielectric permittivity of the FeGa/PZT composite with Hdc due to the delta E effect, magnetostrictive effect of FeGa and mechanism responsible for ME coupling between the FeGa and PZT layers. Furthermore, the FeGa/PZT bilayered composite exhibits both bending and longitudinal vibration modes due to the asymmetrical stress distributions. The maximum ΔZ/Z of the FeGa/PZT composite is about 215% at the antiresonance frequency fa = 28.78 kHz of the bending-mode, which is 2.53 times as high as that at the antiresonance frequency fa = 107.9 kHz of the longitudinal mode, while the maximum ΔC/C of the FeGa/PZT composite is about 406% at the resonance frequency fr = 28.5 kHz of the bending mode, which is 3.5 times as high as that at the antiresonance frequency fa = 106.6 kHz of the longitudinal mode. This study plays a guiding role for the design and corresponding application of magnetic sensors, magnetic-field-tuned electronic devices and multiple frequency ultrasonic transducers.

BaTiO3/(Co0.8Ni0.1Mn0.1Fe1.9Ce0.1O4)x composites: Analysis of the effect of Co0.8Ni0.1Mn0.1Fe1.9Ce0.1O4 doping at different concentrations on the structural, morphological, optical, magnetic, and magnetoelectric coupling properties of BaTiO3

In the present study, composite samples of BaTiO3/(Co0.8Ni0.1Mn0.1Fe1.9Ce0.1O4)x (noted as BTO/(CNMFCO)x) were prepared and their structural, morphological, optical, magnetic, and magnetoelectric coupling properties were investigated. Firstly, the BaTiO3 and spinel ferrite CNMFCO phases were prepared separately through the sol-gel auto-combustion route, then, the composite samples BTO/(CNMFCO)x were made via the solid-state reaction method. The structural, morphological, optical, magnetic, and magnetoelectric coupling properties were examined using X-rays diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR), scanning electron microscope (SEM) coupled with EDX spectrometer, UV–visible diffuse reflectance spectrophotometer (UV–vis DRS), vibrating sample magnetometer (VSM) techniques, and lock-in amplifier, respectively. The successful preparation of biphasic samples was confirmed by XRD and SEM studies. From SEM images, a compact structure with good density was observed. The mean size of BTO grains decreases with increasing the concentration of the magnetic phase. The optical properties have been explored in the UV–visible light range. The extracted band gap energy (Eg) values showed a reduction with the rising of the magnetic phase content. The analysis of magnetization measurements revealed the magnetic character of different composites. It is found that the saturation (Ms) and remanent (Mr) magnetizations are increasing with the rise in the concentration of the magnetic CNMFCO phase (x %). High magnetoelectric voltage coefficients (αME) were attained for different composites with the highest αME value of about 22.8 mV/cm.Oe reached in composite with x content of 20%. The high ME coupling in these composites makes these composites promising candidates to be used in multifunctional devices.

Strain assisted magnetoelectric coupling in ordered nanomagnets of CoFe2O4/SrRuO3/(Pb(Mg1/3Nb2/3)O3–PbTiO3) heterostructures

We have explored the electric field controlled magnetization in the nanodot CoFe2O4/SrRuO3/PMN-PT (CFO/SRO/PMN-PT) heterostructures. Ordered ferromagnetic CFO nanodots (∼300 nm lateral dimension) are developed on the PMN-PT substrate (ferroelectric as well as piezoelectric) using a nanostencil-mask pattering method during pulsed laser deposition. The nanostructures reveal electric field induced magnetization reversal in the single domain CFO nanodots through transfer of piezostrains from the piezoelectric PMN-PT substrate to the CFO. Further, electric field modulated spin structure of CFO nanomagnets is analyzed by using x-ray magnetic circular dichroism (XMCD). The XMCD analysis reveals cations (Fe3+/Co2+) redistribution on the octahedral and tetrahedral site in the electric field poled CFO nanodots, establishing the strain induced magneto-electric coupling effects. The CFO/SRO/PMN-PT nanodots structure demonstrate multilevel switching of ME coupling coefficient (α) by applying selective positive and negative electric fields in a non-volatile manner. The retention of two stable states of α is illustrated for ∼106 seconds, which can be employed to store the digital data in non-volatile memory devices. Thus the voltage controlled magnetization in the nanodot structures leads a path towards the invention of energy efficient high-density memory devices.

Tuning ferroelectrics to antiferroelectrics in multiferroic LaxSr1−xFe12O19 ceramics

The combination of antiferroelectricity (AFE) and ferromagnetism (FM) in one structure would allow the development of new type of multiferroic candidates, which be applicable not only in magnetoelectric memories but also in novel energy storage devices. Here we propose a novel type of multiferroic candidate LaxSr1-xFe12O19, whose room temperature state could betuned from ferroelectrics (FE) to antiferroelectrics by changing x from 0 to 0.5. The emphasis of this paper will be focused on the La0.5Sr0.5Fe12O19 system, in which full AFE and FM coexist. The pure antiferroelectric behavior in La0.5Sr0.5Fe12O19 ceramics is demonstrated by double polarization-electric field (P-E) hysteresis loops, which are fully separated by a linear antiferroelectric AFE component with zero net polarization. The material of La0.2Sr0.7Fe12O19 with the intermediate composition exhibits a hybrid ferroelectric/antiferroelectric state. The recoverable energy density of the antiferroelectric La0.5Sr0.5Fe12O19 phase reaches 14.3 J/cm3. This material demonstrates strong magnetoelectric coupling and giant magnetoresistance (GMR) effect. A 1.1T magnetic field generates electronic polarization up to 0.95uC/cm2, reduce the resistance by 117%, enhances dielectric constants by 540% and right shifts the maximum dielectric loss peak by 208 kHz. The combined functional responses provide an opportunity to develop novel multifunctional electric and energy storage devices.

Insights into the novel magnetoelectric coupling mechanism in soft materials due to Maxwell interactions

This study models the novel ME coupling mechanism in soft materials that are inherently non-magnetoelectric (NME). First, the central physical concept for developing ME coupling in soft NME materials is explained. Following this, the stretch of soft materials under magnetic and stress stimuli is solved by using the obtained Euler–Lagrange equations. Finally, the ME coefficients for various operating modes are analytically derived. The numerical results obtained for the ME coefficients of a ME electret system are in good agreement with the experimental data. The nonlinear interplay between the stress, magnetic field, and ME response is investigated. In addition, the key factors for maximizing the ME coupling are discussed. Based on the proposed model, we present physical insights to support the prospects of achieving magnetic energy harvesting and revealing the physical mechanisms of animals' magnetoreception. This work may provide a simple basis to further create soft ME-like materials with good flexibility and strong ME coupling.

Observation of magnetoelectric effect in the S = 1/2 spin chain compound CoSe2O5 single crystal

The antiferromagnetic structure in the S = 1/2 zigzag spin chain compound CoSe2O5 was recently revealed by neutron scattering. Herein, we provide clear evidence for the linear ME coupling through systematic investigations on magnetic, dielectric, and ferroelectric properties. The simultaneous responses of the b-axis electric polarization (Pb) and dielectric anomaly (εb) against magnetic stimuli along the c-axis are revealed. In addition, both the ferroelectric transition and dielectric anomaly shift from the magnetic Néel temperature TN ∼ 8.5 K toward the low temperature under increasing H applied along the c-axis, providing clear evidence for the magnetism-driven ferroelectricity. The observed off diagonal linear ME effect is in accordance with the prediction based on ME tensor analysis for the magnetic space group Pb′cn. Consequently, our results may allow an interesting opportunity to further exploration of intriguing phenomena and physics of ferrotoroidicity in this linear-ME compound CoSe2O5 due to the existence of the off diagonal term in the ME tensor, similar to the case for LiCoPO4.

Effect of mechanical milling on magnetic, dielectric and magneto-electric properties of Z- type (Ba, Sr) hexaferrites

The Z-type hexaferrites Sr3Co2Fe24O41 (SCFO) and Ba3Co2Fe24O41 (BCFO) were prepared via sol-gel method and were ball milled for different duration to study the effects of reduction in particle on the physical properties of these compounds. The phase formation was confirmed by using X-ray diffraction (XRD) whereas Scanning Electron Microscopy (SEM) was employed to analyze the surface morphologies of these samples. Magnetization measurements i.e. (M-H) at room temperature were performed by using Vibrating Sample Magnetometer (VSM) and it is observed that the magnetic coercive field (Hc) has increased with reduction in particle of the samples i.e., with ball milling. Magneto electric effects of (Ba, Sr) Z-type hexaferrites at room temperature were measured indirectly by examining the change in polarization (P-E loop) with and without magnetic field. It is evident from P-E loops of SCFO that magnetic field affects the electric polarization for all ball-milled samples and it is an indication of ME coupling in these samples at room temperature.

Investigation of spin-phonon coupling and local magnetic properties in magnetoelectric Fe2TeO6

Spin-phonon coupling originated from spin-lattice correlation depends upon different exchange interactions in transition metal oxides containing 3d magnetic ions. Spin-lattice coupling can influence the coupling mechanism in magnetoelectric material. To understand the spin–lattice correlation in inverse trirutile Fe2TeO6 (FTO), magnetic properties and phonon spectra are studied. Signature of short-range magnetic correlation induced by 5/2–5/2 dimeric interaction and magnetic anomaly at 150 K is observed apart from the familiar sharp transition (TN ∼ 210 K) corresponding to long-range order by magnetization and heat capacity measurements. The magnetic transitions and the spin dynamics are further locally probed by muon spin resonance (μSR) measurement in both zero fields (ZF) and longitudinal field (LF) mode. Three dynamically distinct temperature regimes; (i) T > TN, (ii) TN > T > 150 K, and (iii) T < 150 K, are observed. A change in the spin dynamics is realized at 150 K by μSR, though previous studies suggest long-range antiferromagnetic order. The renormalization of phonon frequencies observed in Raman spectra below 210 K suggests the existence of spin-phonon coupling in the material. The coupling strength is quantified as in the range 0.1–1.2 cm−1 following the mean-field and two-spin cluster approximations. We propose that the spin-phonon coupling mediated by the Fe-O2-Fe interbilayer exchange play a significant role in magnetoelectric ME coupling observed in the material.