Room Temperature Magnetization Research Articles

Vacancy-induced magnetic states in TiO2 surfaces

We present a combined experimental and theoretical study of surface-related magnetic states in TiO2. Our experiments on nano-sized thin films of pure TiO2 have suggested that the observed room-temperature magnetism originates from defects, in particular, from the surface of thin films as well as from point defects, such as oxygen vacancies located mainly at the surface. Clarifying this phenomenon is very important for harnessing magnetic properties of pristine TiO2 films in future spintronic applications but a detailed experimental investigation is very demanding. Therefore, quantum-mechanical density functional theory calculations were performed for (i) bulk anatase TiO2, (ii) bulk-like TiO2-terminated vacancy-free (001) surfaces, (iii) vacancy-containing TiO-terminated (001) surfaces, (iv) TiO0.75-terminated (001) surfaces with additional 25% surface oxygen vacancies, as well as (v) oxygen-terminated (001)-surfaces. Our fixed-spin-moment calculations identified both the bulk and the bulk-like terminated vacancy-free TiO2-terminated (001) surfaces as non-magnetic. In contrast, oxygen vacancies in the case of TiO-terminated and TiO0.75-terminated (001) surfaces lead to ferromagnetic and rather complex ferrimagnetic states, respectively. The spin-polarized atoms are the Ti atoms (due to the d-states) located in the surface and sub-surface atomic planes. Last, the O-terminated surfaces are also magnetic due to the surface and sub-surface oxygen atoms and sub-surface Ti atoms (but their surface energy is high).

Doping effect of Fe, Co and W on the structural, electrical and magnetic properties of BaTiO3 ferroelectric ceramics

The main focus of the work is to investigate the effect of Fe, Co and W doping on the structural phase, electric and magnetic properties of classical BaTiO3 ceramic system. In this regard we have prepared the specimen of Ba0.95Co0.05Ti0.5Fe0.33W0.17O3 using solid state method and it is examined from X-Ray technique that tetragonal to hexagonal phase transformation occurs by the influence of substituents. The temperature dependent dielectric analysis depicts increase of TC (ferroelectric transition) along with relaxor phenomenon. Room temperature magnetism and ferroelectricity was observed simultaneously in the present specimen. All the results are likely to be originating from the strong coupling of the incorporation of magnetic ions and oxygen vacancies related hexagonal phase phenomena, which have significant character for modern device application.

Exchange stiffness reduction in Ta substituted NiFe alloys

In magnetic tunnel junctions (MTJs) for memory or sensor applications, insertion of Ta nanolayers at the interface of, or within magnetic layers such as CoFe or NiFe is often employed to enhance the tunneling magnetoresistance, although it also locally reduces the magnetization and modifies the magnetic properties. To properly model the magnetic behavior of such structures, it is important to be able to accurately account for these modifications. In this paper, we investigate experimentally and by means of ab initio calculations, the degradation of magnetic and magneto-dynamic properties of Ni0.81Fe0.19 films doped with small amounts of Ta. Both the calculations and the experiment confirm the expected drop of saturation magnetization parameter with increased Ta doping. It is also found that the exchange stiffness is reduced much faster than the magnetization. Calculations show that the presence of Ta impurities has the greatest effect on the magnetic properties of Ni, the dominant element. For example, the introduction of 10 atomic % Ta reduces the exchange stiffness constant by a factor of 10, while the room temperature magnetization reduces by less than a factor of 3, resulting mainly from a decrease in the Curie temperature from 870 to 420 K. Consequently, the reduction in exchange coupling across Ta nanolayers can significantly modify the detailed magnetic behavior and in particular the propagation of exchange coupling within MTJ multilayers.

Ce substituted NiCo[formula omitted] microspheres and nanoflakes: Comparison on magnetic features

NiCo2−xCexO4 (0.0 ≤ x ≤ 0.08) microspheres (MCs) and nanoflakes (NFs) were synthesized hydrothermally. X-ray diffraction analysis confirmed the cubic microstructure of all the samples. The microsphere and nanoflake morphologies of the samples have been confirmed by SEM, along with EDX, TEM and HR-TEM. The magnetic properties of the NiCo2−xCexO4 (0.0 ≤ x ≤ 0.08) MCs and NFs were investigated via magnetization measurements using a vibrating sample magnetometer. Room-temperature magnetization measurements revealed weak ferromagnetic behavior for both MC and NF samples. Low temperature magnetization measurements showed strong ferromagnetic behavior for the different samples. The magnetic parameters for both samples were found to differ substantially at a given temperature, which is accredited to the differences in the morphology of the MC-like and NF-like samples. Room-temperature magnetization measurements revealed antiferromagnetic or paramagnetic behavior for MC samples and weak ferromagnetic character for NF samples. It was also found that the magnetization magnitude decreased with increasing cerium dopant level, when compared to the host product. The changes in magnetization are linked to the effect of introduced cerium ions and their magnetic states, which could generate structural/morphological changes, changes in the size and surface lattice, redistribution of cations among the crystal lattices, changes in magnetic moment, etc.

Getting saturation magnetization of superparamagnetic nanoparticles more accurately from room-temperature magnetization curve

Getting saturation magnetization of superparamagnetic nanoparticles more accurately from room-temperature magnetization curve

Enhanced magnetic, magnetodielectric, and field-dependent magnetoimpedance correlation in the Bi5Ti3FeO15/Bi2Fe4O9 composites

The physical properties of the Aurivillius Bi5Ti3FeO15 compound are enhanced by adding the magnetic BFO compound. The magnetic, magnetodielectric (MD), and magnetoimpedance (MI) properties of Bi5Ti3FeO15/Bi2Fe4O9 composites are investigated. The samples are prepared by the sol–gel-modified method, and the Rietveld refinement verifies the diphasic nature of the composites. The Raman spectra demonstrate the shifting of the vibrational modes due to adding the BFO phase, which is associated with the BO6 (B = Fe/Ti) octahedral. The maximum shift in Raman modes and bond length of Fe-O is noticed for the x = 0.2 composite. Room temperature magnetization data reveals the highest value of Ms and Mr is found for x = 0.2 composite, which is caused by the interaction among the AFM/FM magnetic ordering. The frequency-dependent MD shows the maximum MD% strength of ∼0.55 % for x = 0.1 and minimum magnetoloss (ML)% of ∼0.08 % for x = 0.3 composites. Field variation of MD data shows ∼30 times enhancement of MD% and ∼7 times reduction of the ML% for x = 0.2 sample as compared to the pure sample. The enhanced MD effect is due to the non-collinear ordering of Fe spins in the BFO sample, which results in the possible inverse Dzyalonskii-Moriya interaction in the composites. Additionally, the Ginzburg-Landau approach confirms that the maximum coupling coefficient γ (6.79 emu−2. g2) is observed for x = 0.4 of the BFO sample. The field-dependent capacitive MI and Cole-Cole plot analysis reveals the capacitive origin behind the MD effect. The non-linear variance of magnetoconductance in the pure sample (x = 0.0) is attributed to the maximum ML%. Hence, the enhanced MD coupling with capacitive MI properties is a great advantage for designing magnetic sensors and storage devices.

Design and Preliminary Experiment of Room-Temperature Bitter Magnet for Compact Gyrotron

Magnetic field system is one of the most crucial components for gyrotron operation. A compact gyrotron with a custom-designed magnet would be a promising continuous radiation source for millimeter-wave power applications. In this article, a design and preliminary experiment of a room-temperature Bitter magnet for developing compact gyrotron are presented. To lengthen the magnetic field homogeneity region without dramatically improving power consumption, a special design that every Bitter segment with different outer radii is adopted. Both in simulation and experimental measurement, the length of the homogeneity region is 120 mm, and homogeneity <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Delta \textit{B}$</tex-math> </inline-formula> / <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\textit{B}$</tex-math> </inline-formula> is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\pm$</tex-math> </inline-formula> 0.9% is obtained. A 5 kV magnetron injection gun (MIG) was designed based on the experimental measurement of this Bitter magnet, in which a velocity ratio of 1.3 and transverse velocity spread of 12% were obtained at current 0.5 A in simulation.

First-principles design of ferromagnetic monolayer MnO2 at the complex interface

Rapidly increasing interest in low-dimensional materials is driven by the emerging requirement to develop nanoscale solid-state devices with novel functional properties that are not available in three-dimensional bulk phases. Among the well-known low-dimensional systems, complex transition metal oxide interface holds promise for broad applications in electronic and spintronics devices. Herein, intriguing metal-insulator and ferromagnetic-antiferromagnetic transitions are achieved in monolayer MnO2 that is sandwiched into SrTiO3-based heterointerface systems through interface engineering. By using first-principles calculations, we modeled three types of SrTiO3-based heterointerface systems with different interface terminations and performed a comparative study on the spin-dependent magnetic and electronic properties that are established in the confined MnO2 monolayer. First-principles study predicts that metal-insulator transition and magnetic transition in the monolayer MnO2 are independent on the thickness of capping layers. Moreover, 100% spin-polarized two-dimensional electron gases accompanied by robust room temperature magnetism are uncovered in the monolayer MnO2. Not only is the buried MnO2 monolayer a new interface phase of fundamental physical interest, but it is also a promising candidate material for nanoscale spintronics applications. Our study suggests interface engineering at complex oxide interfaces is an alternative approach to designing high-performance two-dimensional materials.

Negligible magnetic losses at low temperatures in liquid phase epitaxy grown Y3Fe5O12 films

Yttrium iron garnet (${\mathrm{Y}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12}$; YIG) has a unique combination of low magnetic damping, high spin-wave conductivity, and insulating properties that make it a highly attractive material for a variety of applications in the fields of magnetics and spintronics. While the room-temperature magnetization dynamics of YIG have been extensively studied, there are limited reports correlating the low-temperature magnetization dynamics to the material structure or growth method. Here we investigate liquid phase epitaxy grown YIG films and their magnetization dynamics at temperatures down to 10 K. We show there is a negligible increase in the ferromagnetic resonance linewidth down to 10 K, which is unique when compared with YIG films grown by other deposition methods. From the broadband ferromagnetic resonance measurements, polarized neutron reflectivity, and scanning transmission electron microscopy, we conclude that these liquid phase epitaxy grown films have negligible rare-earth impurities present, specifically the suppression of Gd diffusion from the ${\mathrm{Gd}}_{3}{\mathrm{Ga}}_{5}{\mathrm{O}}_{12}$ (GGG) substrate into the ${\mathrm{Y}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12}$ film, and therefore negligible magnetic losses attributed to the slow-relaxation mechanism. Overall, liquid phase epitaxy YIG films have a YIG/GGG interface that is five times sharper and have ten times lower ferromagnetic resonance linewidths below 50 K than comparable YIG films by other deposition methods. Thus, liquid phase epitaxy grown YIG films are ideal for low-temperature experiments/applications that require low magnetic losses, such as quantum transduction and manipulation via magnon coupling.

Enhanced multiferroicity of Ho0.95Co0.05Fe0.95Ti0.05O3 by co-doping in HoFeO3 nanoparticle system

Nanocrystalline HoFeO3 is a potential multiferroic and will be more useful if its multiferroicity can be enhanced by improving the magnetic and electric ordering. In this regard, co-doping with Co and Ti, was considered in HoFeO3 (HFO) to enhance its magneto-electric behavior and thus synthesize a new monophasic multiferroic, Ho0.95Co0.05Fe0.95Ti0.05O3 (HCFTO). Both the pristine and doped HFO nanoparticles were synthesized in sol–gel route. Rietveld analyses of X-ray diffractograms, confirmed the formation of pure orthorhombic (Pnma) phase of both bare and doped HFO. Presence of the canted antiferromagnetism of bare HFO at room-temperature with antiferromagnetic transition at ∼ 637 K was confirmed in susceptibility vs. temperature variation and by the nature of MH loops. Interestingly, substantial enhancement of magnetism was observed in HCFTO compared to that of bare one, where the room-temperature maximum magnetization is enhanced by 73%. Dielectric strength of HFO (∼48) is also enhanced highly (∼3.4 times) in HCFTO (∼165), and the loss factor is lowered to nearly half. Current density vs. electric field (J-E) curve suggests the presence of polarization at room temperature with negligible leakage loss. Lower leakage loss of HCFTO indicates better multiferroicity than HFO. Direct measurement of ferroelectric loop shows the room-temperature ferroelectricity of bare HFO (Pmax ∼ 0.0041 µc/cm2) well improved (∼1.5 times) in the doped HCFTO (Pmax ∼ 0.0061 µc/cm2) with lower hysteresis loss. Room-temperature magnetoelectric coupling measurements, shows a high value (∼2.47%) of magnetocapacitance in the doped system, which is much higher (∼4.94 times) than the bare one (∼0.5%). All these properties of the sample clearly confirm the co-doping in the HoFeO3 nanoparticle system results in a considerable improvement in its magnetoelectric behavior, and this co-doped Ho0.95Co0.05Fe0.95Ti0.05O3 system can be a promising and potential magnetoelectric multiferroic for device applications.

Monolayer chromium dichloride: An anti-ferromagnetic semiconductor with a high Néel temperature above room temperature

Two-dimensional anti-ferromagnetic materials with room-temperature magnetism are highly desirable for the applications of anti-ferromagnetic spintronic devices. Here, a monolayer anti-ferromagnetic chromium dichloride (CrCl2) with a 1 T′ structure is reported based on first-principle calculations. The structural dynamic stability can be ensured by the lattice distortion of dimerization and the 1 T′ CrCl2 is an anti-ferromagnetic semiconductor with a bandgap of 2.03 eV. Importantly, The dimerization also leads to that the nearest Cr atoms exhibit high anti-ferromagnetic coupling. 1 T’ CrCl2 has a Néel temperature of 386 K according to estimations from a Monte-Carlo simulation using the Heisenberg model. This work provides a two-dimensional material with intrinsic anti-ferromagnetism above room temperature, which is one of the promising candidates for the future nanoscale spintronics.

Law of approach to saturation magnetization with structural and temperature variation in Ni–Zn ferrites

Ni–Zn ferrite of compositional formula Ni0.5Zn0.5Fe2O4 was prepared by co-precipitation method. The effect of heat treatment at 600 °C, 800 °C, 1000 °C and 1200 °C on their structures and hence magnetic properties were investigated. Their phase analysis and morphological studies was done using XRD, FTIR, FT-Raman and SEM-EDAX. Room temperature magnetization loops of the prepared materials were recorded up to a maximum applied field of 15 kOe to study the effect of structural variation on magnetic properties. Further, magnetization loops of Ni–Zn ferrite heated at 1200 °C were recorded at 150 K and 50 K to investigate the variation of magnetic properties at low temperatures. Law of approach to saturation magnetization was applied to all the magnetization curves under investigation. The fitted parameters reveal information on the processes of magnetization, anisotropy constant, and saturation magnetization of Ni–Zn ferrites. Law of approach to saturation magnetization in the form M = M s (1− b/H 2) + cH was also found to be successfully applicable to magnetization curves of all the prepared Ni–Zn ferrites in room temperature as well as low temperatures. Its application and significant results were also discussed in detailed.

Incorporation of Co (x), Al (y) into Bi (0.99) Ba (0.1) Fe (1-x-y) O3 and its effect on the microstructural, magnetic, and dielectric properties

The work is focused on synthesizing Bi (0.99) Ba (0.1) Fe (1-x-y) Co (x) Al (y)O3 with composition (x = 0, y = 0), (x = 0.1, y = 0) and (x = y = 0.1) using solgel method and investigating magnetic and dielectric properties at room temperature. The obtained Nanoparticles in the form of fine powder have undergone pre-sintering at 200 °C for 2 h and after that sintering at 500 °C for 3 h. The structural and morphological studies were investigated using X-ray diffraction (XRD) and FE-SEM. The XRD analysis reveals the presence of BiFeO3 with rhombohedral R3C group along with the impurity phases. The crystallite size is found to decrease along with the shrinkage in Lattice Constant. The SEM images show the formation of irregular and heterogeneous structures. It has been observed that the addition of Co followed by Al is found to reduce impurity phases. The presence of Co and Al is confirmed by EDX mapping. The VSM (Vibrating sample magnetometer) is used to investigate room-temperature magnetism by plotting the Hysteresis loop. The magnetic study reveals that subsequent addition Co and Al has offered improved magnetic properties attaining maximum Hc =1570 Oe at room temperature. The dielectric response as a function of Frequency from 100 Hz to 10 MHz is observed. The change in the dielectric constant and reduction in dielectric loss are observed.

Room-Temperature Magnetism in 2D MnGa4 -H Induced by Hydrogen Insertion.

2D room-temperature magnetic materials are of great importance in future spintronic devices while only very few are reported. Herein, a plasma-enhanced chemical vapor deposition approach is exploited to construct the 2D room-temperature magnetic MnGa4 -H single crystal with a thickness down to 2.2nm. The employment of H2 plasma makes hydrogen atoms can be easily inserted into the MnGa4 lattice to modulate the atomic distance and charge state, thereby ferrimagnetism can be achieved without destroying the structural configuration. The as-obtained 2D MnGa4 -H crystal is high-quality, air-stable, and thermo-stable, demonstrating robust and stable room-temperature magnetism with a high Curie temperature above 620K. This work enriches the 2D room-temperature magnetic family and opens up the possibility for the development of spintronic devices based on 2D magnetic alloys.

Permanent Porosity in the Room-Temperature Magnet and Magnonic Material V(TCNE)2.

Materials that simultaneously exhibit permanent porosity and high-temperature magnetic order could lead to advances in fundamental physics and numerous emerging technologies. Herein, we show that the archetypal molecule-based magnet and magnonic material V(TCNE)2 (TCNE = tetracyanoethylene) can be desolvated to generate a room-temperature microporous magnet. The solution-phase reaction of V(CO)6 with TCNE yields V(TCNE)2·0.95CH2Cl2, for which a characteristic temperature of T* = 646 K is estimated from a Bloch fit to variable-temperature magnetization data. Removal of the solvent under reduced pressure affords the activated compound V(TCNE)2, which exhibits a T* value of 590 K and permanent microporosity (Langmuir surface area of 850 m2/g). The porous structure of V(TCNE)2 is accessible to the small gas molecules H2, N2, O2, CO2, ethane, and ethylene. While V(TCNE)2 exhibits thermally activated electron transfer with O2, all the other studied gases engage in physisorption. The T* value of V(TCNE)2 is slightly modulated upon adsorption of H2 (T* = 583 K) or CO2 (T* = 596 K), while it decreases more significantly upon ethylene insertion (T* = 459 K). These results provide an initial demonstration of microporosity in a room-temperature magnet and highlight the possibility of further incorporation of small-molecule guests, potentially even molecular qubits, toward future applications.

Features of the magnetization in ceramics Bi0.86Sm0.14Fe1-xMnxO3 in the rhombohedral - orthorhombic morphotropic phase boundary

Crystal structure of the ceramic compounds Bi0.86Sm0.14Fe1-xMnxO3 prepared by solid state reaction method was studied using X-ray diffraction, scanning electron microscopy and Raman spectroscopy; magnetometry measurements were performed to study magnetic properties and to investigate a correlation between the magnetic and crystal structures of the compounds. The compounds with 0 = x ≤ 0.1 are characterized by the coexistence of the polar rhombohedral and the antipolar orthorhombic phases, an increase of Mn doping causes a stabilization of the orthorhombic phase. Room temperature magnetization data show a gradual reduction of the remanent magnetization with an increase of Mn concentration, while a decrease of temperature causes a nontrivial reduction of remanent magnetization which is determined by a transformation of the non-collinear antiferromagnetic structure towards the collinear antiferromagnetic structure. The magnetic state of the compounds notably depends on the phase ratio of the coexisting structural phases and consists of the antiferromagnetic phases associated with the respective rhombohedral and the orthorhombic phases as well as the ferromagnetic component associated with the phase boundary spins. An evolution of the mentioned magnetic subsystems is discussed as a function of the chemical composition and temperature.

Investigation on structural, magnetic and optical properties of Sm–Co Co-substituted BiFeO3 samples

Abstract Sol–gel derived Sm–Co co-substituted BiFeO3 ceramics (Bi1–x SmFe1–x Co x O3 with x = 0.0, 0.01, 0.02 and 0.03; named as BFO, BSFCO-1, BSFCO-2 and BSFCO-3, respectively) were investigated for structural, vibrational, magnetic and optical properties. Distorted perovskite rhombohedral structure with R3c crystal symmetry has been established in X-ray diffraction (XRD) patterns analysis by Rietveld refinement and detailed structural parameters like lattice constants, unit cell volume, bond angles, bond length etc. have been evaluated. Raman spectra further confirmed typical rhombohedral structure of BiFeO3 by exhibiting 13 clear Raman active phonon (9E + 4A) modes along with second order modes in the wave number range 50–1500 cm−1. Fourier Transform Infrared (FTIR) spectra showed the presence of Fe–O and Bi–O bands and the calculated Fe–O bond length was in good agreement with that obtained from Rietveld analysis. Room temperature magnetization versus magnetic field (M–H) measurement using Vibrating Sample Magnetometer (VSM) showed enhancement of ferromagnetic ordering parameters with increasing Sm–Co content in BiFeO3 samples. The maximum magnetization values increased from 0.237 emu g−1 for BFO sample to 1.167 emu g−1 for BSFCO-3 sample along with increase in remnant magnetization values. The optical property of Bi1–x SmFe1–x Co x O3 samples was investigated by estimating the energy band gap using UV–Visible spectroscopy. The calculated values of energy band gap were varied in the range 2.46 eV–1.81 eV indicating tuning of energy band gap with Sm–Co co-substitution in BiFeO3 sample.

Topologically Frustrated Graphene Antidot Lattice Semiconductors with Room-Temperature Magnetism

Realizing graphene spintronics is intriguing due to the weak spin–orbital coupling; however, developing intrinsic room-temperature magnetic semiconductors in graphene is still a great challenge. Graphene antidot lattices (GALs), as a type of regular vacancy graphene, exhibit topology-dependent magnetism and offer an ideal platform to achieve room-temperature magnetic semiconductors. Recently, on-surface-synthesized open-shell [n]triangulene polymers as topologically frustrated graphene nanoflakes (GNFs) are the new building blocks to construct topologically frustrated GALs with robust magnetism. Herein, on the basis of the density functional theory calculations, we report seven magnetic GAL semiconductors by assembling two types of open-shell GNFs with topological frustration, that is, isomeric π-extended heptauthrene (cis triangulene dimer) and heptazethrene (trans triangulene dimer). Our results demonstrate that topologically frustrated GALs are semiconductors with either bipolar ferromagnetism or antiferromagnetism, inheriting the topologically frustrated magnetism from their building blocks. In particular, three ferromagnetic and two antiferromagnetic GALs exhibit above room-temperature magnetic order with their Curie or Néel temperatures varying from 507 to 527 or 366 to 391 K, respectively. This study provides a feasible route to obtain topologically frustrated GAL semiconductors with the above room-temperature magnetism from open-shell GNFs for graphene spintronics applications.

Chemical Tuning Meets 2D Molecular Magnets (Adv. Mater. 5/2023)

Molecular Magnets In article number 2208919, Yulong Huang, Shenqiang Ren, and co-workers report in situ chemical tuning to realize the controllable transformation from low-temperature magnetic order to room-temperature hard magnetism in a layered molecular-based magnet. A coercivity of 8500 Oe and energy product of 0.6 MG Oe are demonstrated, providing a universal approach to control organic magnetism.

Magnetoelectric coupling at microwave frequencies observed in bismuth ferrite-based multiferroics at room temperature

• Room-temperature single phase multiferroic materials was obtained • Magnetoelectric coupling was observed at microwave (GHz) frequency • The coupling suggests a dynamic interaction between magnetic moments and ferroelectric polarization 0.63Bi 0.99 La 0.01 Fe 1- x Mn x O 3 -0.33BaTiO 3 -0.04Na 0.5 Bi 0.5 TiO 3 ( x = 0.10, 0.15, and 0.20) ceramics have been prepared by solid state reaction, and their structural, ferroelectric, ferromagnetic, piezoelectric, and magnetoelectric properties are studied. Except for the x = 0.2 composition, the X-ray diffraction and SEM-EDX analysis on the sintered ceramics show that the samples are single-phase, rhombohedral perovskites at room temperature. The introduction of Mn ions leads to a small deterioration in the ferroelectric and piezoelectric properties, whilst the room-temperature magnetization increases upon doping. The optimal multiferroic properties are obtained for the x = 0.15 composition. The magnetoelectric coupling in this sample was evidenced by the anomalies occurring simultaneously in the dielectric permittivity and magnetic permeability spectral profiles in the microwave region. Such a coupled phenomenon can be attributed to a dynamic interaction between magnetic moments and ferroelectric polarization.