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Abstract

A polycrystalline sample of Sr(Mn_1/2Nb_1/2)O₃ (SMNO) was synthesised via the solid-state reaction method, confirming a single-phase perovskite structure. Room-temperature XRD analysis revealed a tetragonal crystal system. Micro-Raman spectroscopy exhibited broad peaks, suggesting the presence of a vibrational band and ferroelectric characteristics. Dielectric properties were investigated over a broad frequency (100–1 MHz) and temperature (24–360°C) range, revealing strong low-frequency dispersion, a very high dielectric constant and loss (∼6). A broad permittivity peak was observed at 280°C across all measured frequencies. The frequency and temperature dependence of the ac conductivity (σ_ac) suggest a thermally activated relaxation mechanism. Impedance spectroscopy indicated that the dielectric and conductive properties of the material arise from the contributions of bulk, grain boundaries and electrode effects. Magnetic measurements identified an antiferromagnetic transition at 41 K, co-existing with a low-temperature ferromagnetic phase. The growing demand for miniaturised and versatile electronic components drives our strong interest in developing dielectric ceramics. These materials are critical for applications such as capacitors, sensors, actuators and transducers.

Keywords

ferroelectricity dielectric UV-visible impedance ferromagnetic

Introduction

There are several technical applications for oxides with complicated perovskite structures and high dielectric constants in microelectronics.^1,2 Both memory storage devices and capacitors, which need materials with a high dielectric constant, frequently use these materials. For many real-world applications, this is a disadvantage since their dielectric characteristics tend to change dramatically with temperature. Since regulations restrict lead utilisation, the majority of dielectric materials with perovskite structures also include a significant quantity of lead, which raises environmental problems. As a result, dielectric materials with lower lead concentration or ceramics that are completely lead-free are becoming more and more necessary to solve these environmental issues.

Ceramics of perovskite structure (ABO₃) have been showing rich and diverse physical properties, which are of immense potential for different industrial applications.^3–9 This structure can accommodate two or more cations at both A-site and B-site, making it a complex perovskite of the form (A₁, A_2, A₃…..)(B₁, B_2, B₃…..)O₃. In this complex perovskite, the material can be tailored with different cation substitutions to get the desired result. When the B-site cation has an empty d⁰ orbital, it produces Ferroelectricity (the material that possesses spontaneous electric polarisation, which an electric field can switch) like BaTiO₃, Li NbO_3, etc. When the B-site cation is occupied with a cation having a partially filled d orbital, it generally shows magnetic order. In the last several years, scientists have been substituting both d⁰ cation and dⁿ cation at the B-site in complex perovskite structures to attain multifunctional materials. As a result, a very interesting material is formed, called a multiferroic material, where both Ferroelectricity and magnetic order are achieved in the same phase.^10–16

These multiferroic materials have found tremendous applications in device fabrication, like memory storage devices, spintronics devices, sensors and actuators. One of the most studied complex perovskite multiferroics is Pb(Fe_1/2Nb_1/2)O₃.¹⁷ It shows very strong electric polarisation but weak magnetic behavior. Recently, Pb has been replaced by other cations like Ba, Ca, etc., to get rid of toxic Pb. In this study, we have replaced Pb by Sr at the A-site and Fe by Mn at the B-site to make single-phase Sr(Mn_1/2Nb_1/2)O₃, which is expected to be a lead-free multiferroic with a complex perovskite structure.

The giant dielectric response of Sr(Fe₁_/₂Nb₁_/₂)O₃ was reported by Raevski et al.,¹⁸ and its magnetic properties were examined by Tezuka et al.¹⁹ However, until the recent study by Saha and Sinha,²⁰ there were few thorough investigations into its dielectric behavior over a wide range of temperatures and frequencies. The Maxwell-Wagner polarisation process was used in earlier studies²⁰ to explain the high dielectric constant of Sr(Fe₁_/₂Nb₁_/₂)O₃ ceramics. However, more complicated behavior has been demonstrated by related compounds such as Ba(Fe₁_/₂Nb₁_/₂)O₃²¹ and Ba(Fe₁_/₂Ta₁_/₂)O₃,²² indicating that more investigation into the underlying physical sources of dielectric relaxation and the gigantic dielectric response in Sr(Fe₁_/₂Nb₁_/₂)O₃ is still required.

In the present work, a dielectric study of the strontium iron niobate SrFe_1/2Nb_1/2O₃ ceramic prepared by a solid-state reaction technique is presented. The introduction of transition metals at the B-site has been explored in previous literature; however, there is limited research on several regions, such as optical, electrical and dielectric, in some distinct regions. This gap has led to a wealth of scientific investigation and potential applications. In this article, we investigated the structural and micro-structural properties of the material. In addition, we have briefly studied dielectric, impedance and transport in a wide temperature range of 24–360°C and a frequency range of 100 Hz to 1 MHz. Also, the optical study, that is, UV and Raman spectroscopy, was conducted to obtain the bandgap and molecular vibrations of the material. The impact of weak ferromagnetism at low temperatures is apparent from the M–H loop.

Experiment

Sr(Mn_1/2Nb_1/2)O₃ with polycrystalline structure were synthesised through the solid-state method²³ using AR-grade precursors: SrCO₃ (98%, Loba Chemicals, India), Mn₂O₃ (98%, Alfa Aesar) and Nb₂O₅ (99%, Loba Chemicals, India).

The reactive powders were mixed mechanically in an appropriate stoichiometric ratio. The above powders were mixed completely under dry conditions for 1 h in an agate mortar, followed by a wet treatment (e.g., methanol) for 2 h to achieve a homogeneous mixture. Then the mixed powder in a platinum crucible was calcined at 1200°C for 6 h. The powder so obtained after calcination was cold pressed into pellets (dia. 10 mm) under an uniaxial pressure of 5 × 10⁶ N/m² using polyvinyl alcohol (PVA) as the binder. The pellets were then sintered at 1250°C for 6 h. The pellets were finally coated with silver paint, followed by drying at 150°C for 2 h prior to electrical measurements.

To know the compound formation, X-ray diffraction (XRD) studies were carried out (X-ray powder diffractometer (Rigaku, PANalytical X’Pert). The XRD pattern of the calcined powder was recorded at room temperature with CuK_α radiation (λ = 1.5405 Å). An X-ray study was carried out in a wide range of Bragg angles (20° ≤ 2θ ≤ 80°) at a scan speed of 3°/min. Micro Raman spectroscopic behavior was studied via Renishaw invia Reflex (UK) spectrometer. Electrical analysis was carried out using a computer-controlled impedance analyser “HIOKI LCR METER” in the frequency range from 100 Hz to 1 MHz in a temperature range of 24‒360°C. The acquisition of data was monitored using frequency and temperature. The magnetic measurements are taken in SQUID-VSM.

Results and discussion

XRD study

Figure 1(a) depicts the SMNO X-ray diffraction pattern at ambient temperature. The acquired findings show that the samples have a tetragonal perovskite structure in a single phase without any additional impurity peaks. To substantiate these claims, the powder underwent Rietveld refining. The Fullprof software was used to carry out the structural refinement. After refinement of the samples, the numbers obtained from R-values and χ² are recorded. The refinement parameters are a = b = 5.593575 Å; c = 7.967321 Å); c/a = 1.4243, R_Bragg − 13.74; χ ² − 2.58. It shows the tetragonal structures of space group I 4/m c m. The success of a Rietveld refinement is evaluated by the plot difference between observed and calculated patterns (Figure 1(b)). The schematic representation of a unit cell of SMNO ceramic is presented in Figure 1(c). The reﬁned structure has been obtained using data given in Table 1 and the VESTA program (v.3.0 for Windows). The refined atomic positions of the SMNO sample are provided in Table 1.

Figure 1.

(a) Room temperature XRD diffraction pattern, (b) Rietveld refinement, and (c) Unit Cell structure of SMNO compound.

Table 1.

The refined atomic positions (Wyckoff and occupancy) of SMNO sample.

Atoms	Wyckoff	x	y	z	Occupancy
Sr	4b	0	0.5	0.25	1
Mn	4c	0	0	0	0.5
Nb	4c	0	0	0	0.5
O1	4a	0	0	0.25	1
O2	16k	0.25	0.5	0	1

The average crystallite size, calculated using the Debye-Scherrer formula (D = Kλ/βcosθ) on the most intense XRD peak, was 28.30 nm. This peak was selected for its minimal influence from defects like stacking faults, twinning and texturing. Here, D is the average crystallite size, K is the form factor, β is the full-width half maxima of the most significant peak in radians, and λ= 0.1540 nm is the X-ray wavelength. According to the standard model for polycrystalline materials, the density of dislocations (ρ) can be estimated from the crystallite size. Assuming the crystallites function as sub-grains bounded by networks of dislocations, the relationship is given by ρ = 1/D². Applying this model yields a dislocation density of 1.24 × 10¹⁵ m².

Raman study

Figure 2 shows the micro Raman studies at room temperature of the prepared sample. Broad peaks are obtained at 304, 577, 694 and 818 cm⁻¹. The peak at 304 cm⁻¹ may be due to the LO₂-TO₃ phonon, which may arise from local symmetry breaking due to the tilting of the octahedral and distortions of the polar order. The peak at 577 cm⁻¹ may be assigned to B-O displacement, while the peak at 694 cm⁻¹ may be due to the symmetrical stretching of BO₆ octahedra. The peak at 818 cm⁻¹ may be a signature of ferroelectricity in the sample and may represent the vibrations of Mn⁺³ and Nb⁺⁵ ions. The broadening of peaks may be due to lattice disorder.²⁴ Raman spectroscopy revealed several key vibrational modes. The peaks at 694 and 304 cm⁻¹ are characteristic of SrCO₃, associated with its in-plane bending, symmetric stretching and lattice vibrations.²⁵ A peak at 818 cm⁻¹, potentially linked to Mn³⁺ and Nb⁵⁺ vibrations, suggests the presence of ferroelectric properties. The observed peak broadening indicates lattice disorder within the material.²⁴

Figure 2.

Room temperature Micro Raman spectra of Sr(Mn_1/2Nb_1/2)O₃.

Dielectric and electrical properties

Frequency variation plays a crucial role in the performance and functionality of advanced photonic and electronic systems,^26–27 such as two-channel whispering gallery mode (WGM) self-injection locking lasers and relaxor antiferroelectrics for neuromorphic computing.^28–29 In the case of WGM self-injection locking lasers used in hybrid optically pumped atomic comagnetometers, precise frequency tuning enables enhanced laser stability, reduced linewidth and improved sensitivity to magnetic fields, which are essential for accurate atomic spin measurements. Frequency control between the two laser channels ensures proper synchronisation with atomic transitions, thereby boosting the overall precision and reliability of the comagnetometer. Similarly, in relaxor antiferroelectric materials, frequency-dependent dielectric responses are key to emulating synaptic behavior in neuromorphic systems. By applying variable frequencies, it becomes possible to modulate polarisation dynamics and achieve tunable resistive states, mimicking the adaptive learning processes of biological neurons. Together, these applications demonstrate how frequency variation is a powerful tool for optimising performance in cutting-edge technologies across both quantum sensing and brain-inspired computing. Here, we have studied the frequency variation of the dielectric constant and loss.

The frequency response of dielectric properties, that is, variation of relative permittivity (ε_r) and loss tangent (tan δ) with frequency at room temperature for SMNO (Figure 3) shows a marked dispersive characteristic in both the permittivity and loss tangent pattern. The value of relative permittivity attains a value of around 10,000 at a frequency of 100 Hz; at the same frequency, the loss tangent also attains a very high value of almost 3.5. This lossy behaviour of the sample may be attributed to the oxygen ion vacancies produced due to the fluctuation of oxidation states of Mn in the oxygen octahedra. Both ε_r and tan δ values decrease with increasing frequency up to 10 kHz, which is a typical behavior of dielectric and ferroelectric materials. With increasing frequency, some of the dynamic polarisation phenomena cease. However, beyond 10 kHz, while there is a plateau followed by a sharp fall of ε_r, the value of tanδ slowly increases with increasing frequency. So, the overall frequency response of the material in this observed frequency window may be attributed to low-frequency relaxation phenomena, deviation from Debye-type behavior and possible grain boundary barrier effect.³⁰

Figure 3.

The frequency variation of relative permittivity (ε_r) and loss tangent (tan δ) of Sr(Mn_1/2Nb_1/2)O₃ at different temperatures (50–300°C).

Figure 4(a) and (b) show respectively the variation of relative permittivity (ε_r) and the loss tangent tan δ with temperature at different frequencies, that is, 50 kHz, 100 kHz and 1 MHz. ε_r for the material shows very high values, that is, 5739, 5476 and 3353, respectively, for 50 kHz, 100 kHz and 1 MHz at 24°C, while the tanδ value lies below 0.6 for all frequencies at this temperature. Both ε_r and tanδ increase with temperature for all frequencies. An anomaly in the ε_r vs. temperature pattern is observed in the range 100‒250°C and finally, a diffused peak is observed at 280°C for all frequencies. The peak values of ε_r are 24,250, 21,600 and 17,390 for frequencies 50 kHz, 100 kHz and 1 MHz, respectively. The tanδ vs. temperature pattern also shows a rise of tan δ with increasing temperature and an anomaly in the temperature range 100‒200°C with a peak at 324 °C for frequency 1 MHz. In contrast, for lower frequencies, the value reaches the limiting value of the instrument.

Figure 4.

(a) Variation of relative permittivity (ε_r) of Sr(Mn_1/2Nb_1/2)O₃with temperature at different frequencies i.e., 50 kHz, 100 kHz and 1 MHz and (b): Variation of loss tangent tanδ of Sr(Mn_1/2Nb_1/2)O₃with temperature at different frequencies i.e., 50 kHz, 100 kHz and 1 MHz.

An exceptionally high value of relative permittivity with tan δ lying below 1.0 up to a temperature of around 200°C is a remarkable feature for SMNO. The diffused peak at 280°C for all frequencies may be attributed to a possible ferroelectric transition of this material. Also, due to the comparable ionic radii of the B-site cations in the perovskite structure, the distribution of these cations may be random, which consequently may lead to an order-disorder phase transition. With a high value of tan δ, the material shows a lossy behaviour. This lossy behavior may be attributed to oxygen ion vacancies due to fluctuation of oxidation states of Mn in the oxygen octahedra.

The application of dielectric materials under electric fields has enabled significant advancements across various high-performance technologies. For instance, electric current-induced dislocation slip and grain boundary alignment demonstrate how dielectric behavior can influence microstructural evolution in conductive or semiconductive materials, enhancing their mechanical and functional properties.³¹ In advanced layered structures such as alternating Ti₃C₂T_x/Co multilayers, the integration of dielectric components and conductive phases, especially with engineered interfaces like Co “frosting,” improves electromagnetic wave absorption and infrared stealth capabilities by tailoring dielectric polarisation and impedance matching.³² Additionally, in the domain of neuromorphic computing, core–shell nanowire memristors utilising quasi-2D filament confinement highlight how controlled dielectric properties enable reliable and scalable electronic synapses.³³ These developments underscore the importance of dielectric materials in directing charge transport, field-induced phenomena and overall device performance. A comparison study regarding the dielectric constant has been reported in Table 2.

Table 2.

Comparative values of the dielectric constant of different compounds.

Compounds	dielectric constant	Ref.
SrFe0.5Nb0.5O₃	∼10³–10⁵	³⁴
Sr(Mn_1/2Nb_1/2)O₃	∼5 x 10³	This work

Impedance study

Resistance has a significant impact on the overall impedance of an electrical circuit, particularly in alternating current (AC) systems. Impedance, which represents the total opposition to current flow, consists of both resistance (the real part) and reactance (the imaginary part from inductors and capacitors).³⁵

Figure 5 shows the variation of real (Z′) and imaginary parts of impedance (Z″) as a function of frequency at different temperatures. The pattern variation of real (Z′) impedance as a function of frequency shows a low-frequency dispersive region followed by a merger into a plateau region. Also, the value of Z′ decreases both with increasing temperature and frequency. The decrease of Z′ with rise of temperature is a typical semiconducting property with the negative temperature coefficient of resistance (i.e., NTCR type behavior), while the decrease of Z′ with increasing frequency and finally merging on a plateau irrespective of temperature shows a thermally activated ac conductivity and release of space charge. These results indicate a possibility of an increase in the ac conductivity of the material with a rise in temperature in the high frequency region, possibly due to the release of space charge as a result of a lowering in the barrier properties of the material.

Figure 5.

Variation of real (Z′) and imaginary (Z″) part of impedance of Sr(Mn_1/2Nb_1/2)O₃ with frequency (100 Hz–1 MHz) at different temperatures (50–300°C).

The loss spectrum (variation of imaginary impedance (Z″) with frequency) at different temperatures in Figure 5 shows the appearance of peaks at a characteristic frequency dependent on temperature. It can be related to the type and strength of the electrical relaxation phenomenon occurring in the material. A significant broadening of the peaks with a rise in temperature and their asymmetric nature suggests the presence of a temperature-dependent relaxation process with a spread of relaxation times.

Conductivity study

The conductivity spectra (i.e., the variation of a.c. conductivity [σ_ac] as a function of frequency) at different temperatures (50–325°C) are shown in Figure 6. At almost all temperatures, the spectra show a low-frequency plateau region followed by high-frequency dispersion. The frequency-independent plateau in the low frequency range is associated with the dc conductivity σ_dc.

Figure 6.

Variation of ac conductivity (σ_ac) with frequency of Sr(Mn_1/2Nb_1/2)O₃ at different temperatures with power law fitting at 150°C (inset).

This plateau region extends to higher frequencies with increasing temperature. This type of conductivity behavior is well explained by Jonscher's power law³⁶ given by the formula σ (ω) = σ_dc + Aωⁿ, where n is the frequency exponent (0 ≤ n ≤ 1) and A is a pre-exponential factor. The fitting of the power law with experimental data at 150°C is shown in the inset of Figure 6. The values of σ_dc are calculated at different temperatures of the conductivity spectra by fitting them with the power law.

A graph (Figure 7) is plotted between σ_dc and the inverse of absolute temperature (1000/T). The graph can be split into three different linear regions with three different slopes obeying the Arrhenius formula σ_dc = σ₀ e^−Ea/kT_, where σ₀ is the pre-exponential factor.

Figure 7.

Variation of dc conductivity (σ_ac) with inverse of absolute temperature of Sr(Mn_1/2Nb_1/2)O₃.

The activation energy (E_a) calculated from the slopes is 0.12 in the low temperature range (50−100°C), 0.21 in the mid temperature range (125−225°C) and 0.49 in the high temperature range (250−325°C).

The calculated values of activation energy in different temperature ranges show that the bulk conductivity at low temperature, grain boundary conductivity at the mid temperature and electrode response dominate at the high temperature region of conductivity.¹⁶ Also, the value of conductivity increases by two or three orders with an increase in temperature. So, the material shows NTCR behaviour like that of a semiconductor. The overall dielectric response, along with the heterogeneous conduction process, indicates that the material might have a diffused ferroelectric transition near 280°C along with Maxwell-Wagner polarisation, oxygen ion vacancies (V_O) induced dielectric relaxation and space charge polarisation.^37,38

Nyquist plot study

To gain more insight into the electrical microstructure of the material, a complex impedance analysis was performed. Figure 8(a) and (b) shows the graph plotted between the imaginary (Z″) versus real (Z′) part of the complex impedance (Nyquist plot) at different temperatures. The semicircles appear to be stretched, indicating a distribution in time constant characteristics, which supports the diffused nature of the phase transition of the material and departure from Debye-like behavior. The Nyquist plots at higher temperatures (≥225°C) show an additional contribution due to the grain boundary effect to the electrical response of the material. The assignment of the two semi-circular arcs to electrical response due to grain interior and grain boundary can be expressed as an equivalent electrical circuit built up by cascading of two parallel resistance and capacitance (RC circuits) connected in series, each being responsible for a semicircle in the experimental electrical response and appear to be consistent with the ‘brick-layer model’ for a polycrystalline material.³⁹ Generally, to represent the departures from Debye-like ideality, a constant phase element, CPE, is also included with the parallel RC element. The equivalent circuit (inset) and a representative fitting curve (solid curve) according to this circuit with the experimental data at 250°C (scattered points) are shown in Figure 8(c).

Figure 8.

The graph plotted between the imaginary (Z″) versus real (Z′) part of the complex impedance from (a) 50 to 200°C, (b) 225°C to 325°C (c) The equivalent circuit (inset) and a representative fitting curve (solid curve) according to this circuit with the experimental data at 250°C (scattered points).

All plots have been fitted as per the equivalent circuit mentioned above and the values of Bulk capacitance C_b at different temperatures are calculated. A graph is plotted between C_b and temperature, shown in Figure 9. The graph shows a broad peak near 280°C, which is further evidence of the fact that the diffused phase transition in the material near 280°C is not due to the extrinsic factors.

Figure 9.

Variation of bulk capacitance (C_b) with temperature for Sr(Mn_1/2Nb_1/2)O₃.

Magnetic properties

Magnetisation switching via electric field is an emerging technique that allows control of a material's magnetic state without the need for external magnetic fields or high current densities. This approach is highly desirable for low-power spintronic devices and next-generation memory technologies. By applying an electric field, the magnetic anisotropy or exchange interactions within certain multiferroic or magnetoelectric materials can be altered, leading to a reversal or reorientation of the magnetisation direction.^40–42 This effect is particularly significant in systems where electric polarisation and magnetisation are strongly coupled, such as in magnetoelectric heterostructures or strain-mediated ferroelectric/ferromagnetic composites. Unlike conventional methods that rely on current-induced magnetic fields, electric field-driven switching offers energy efficiency, faster operation and scalability. As research advances, this mechanism holds great promise for developing ultra-low-power, non-volatile memory and logic devices.

Figure 10(a) shows magnetisation (M) in both zero-field-cooled (ZFC) and field-cooled (FC) modes measured at 0.05 T of the SMNO ceramic sample. Magnetisation increases gradually with the decrease in temperature below 300 K, and around 41 K, a kink is observed at both magnetic fields without any observable shift in the temperature. Further, there is no bifurcation in ZFC and FC magnetisation modes around this kink, indicating a thermodynamic transition. However, a bifurcation in ZFC and FC starts below 15 K, which is quite prominently visible when drawn in log scale, as shown in Figure 10(b). The kink at 41 K indicates a magnetic order transition. The magnetisation again increases continuously below this kink temperature, showing the existence of weak ferromagnetism.

Figure 10.

(a) Magnetisation (M) versus temperature (T) graph in ZFC and FC mode at 0.05 T (b) M-T curve in log scale.

The effect of weak ferromagnetism at low temperature is evident from the nonlinearity in the M–H hysteresis loop with a small opening in the loop at 10 K shown in Figure 11. It has been established that the magnetic order in perovskites can show both antiferro and ferromagnetic components.^43,44

Figure 11.

Magnetisation (M) versus Field (H) at 300 K and 10 K of the sample.

This type of metastable magnetic state in the polycrystalline material is observed in systems when ferromagnetic interactions are introduced randomly in a predominantly antiferromagnetic matrix.¹⁶ Here, Mn⁺³ is in a high-spin state, but the distributions of Nb⁺⁵ and Mn⁺³ are random at the B-site. Therefore, some of the superexchange interactions may give rise to the observed weak ferromagnetism and a random distribution of ferromagnetic interactions in the present system. Thus, it may be concluded that the distribution of Nb⁺⁵ and Mn⁺³ is actually random in our sample, which also has a significant effect on its dielectric properties. Nevertheless, this noteworthy low-temperature feature needs to be investigated in detail to ascertain its nature and origin and also its relation to the magnetoelectric coupling in this system. From a view of geometry, the antiferromagnetism is based on 180° of B-O-B′ bond angle, and the bending of the B-O-B′ bonding in the distorted perovskite would give additional magnetic interaction. By decreasing exchange interaction and increasing Dzyaloshinskii-Moriya interaction, week ferromagnetic order might be induced. The bifurcation in ZFC and FC mode in the M-T curve below 15 K needs further investigation to find a possible spin glass transition in the material.

Conclusion

A polycrystalline single-phase ceramic sample, SMNO, has been successfully prepared, which is confirmed through a room temperature XRD study. The micro Raman studies indicate a signature of ferroelectricity in the material. The diffused peak in the permittivity pattern at 280°C shows a possible ferroelectric transition in the material. The impedance data were analysed according to an equivalent circuit selected on the basis of conductivity spectra and the Nyquist plot. Analysis of the ac conductivity (σ_ac) as a function of both frequency and temperature indicates the existence of a thermally activated relaxation process. The variation of bulk permittivity with temperature was compared with the temperature dependence of relative permittivity measured at constant frequencies. An order disorder phase transition, along with grain, grain boundary and electrode effects, contributes to the overall dielectric response of the material. A kink at 41 K and an increase in magnetisation in the M-T graph below this temperature show an antiferromagnetic transition with the onset of ferromagnetism below 41 K The nonlinear behavior of magnetisation as a function of a field with a finite opening in the M–H loop, at 10 K, gives further evidence of ferromagnetism. Our research is motivated by the miniaturisation and application flexibility in electronics, leading to a focus on the design and fabrication of innovative dielectric ceramics. These materials are essential for prevalent devices, including capacitors, transducers, sensors and actuators.

Footnotes

Acknowledgement

The authors acknowledge to IMMT BBSR for several characterisation.

ORCID iD

Raj Kishore Mishra

Ethical considerations

All authors have read and agreed to the final version of the manuscript. The work is original,and it has not been communicated or published anywhere. The authors declare no conflict of interest.

Author contributions

Conceptualisation: Raj Mohan Mohanty,Raj Kishore Mishra,Sabyasachi Parida;methodology: Raj Mohan Mohanty,Srikanta Behera,Tapan Dash;formal analysis and investigation: Raj Mohan Mohanty,Raj Kishore Mishra,Srikanta Behera;writing‒original draft preparation: Raj Mohan Mohanty,Raj Kishore Mishra;writing‒review and editing: Raj Kishore Mishra,Sabyasachi Parida,Tapan Dash;supervision: Raj Kishore Mishra,Sabyasachi Parida.

Funding

The authors received no financial support for the research,authorship,and/or publication of this article.

Declaration of conflicting interests

The authors declared no potential conflicts of interest with respect to the research,authorship,and/or publication of this article.

Author biographies

Raj Mohan Mohanty serves as an Assistant Professor of Physics at B. J. B. Autonomous College,and is also associated with C.V. Raman Global University,Bhubaneswar Department of Physics. He is dedicated to teaching both undergraduate and postgraduate students,guiding academic projects,and contributing to curriculum enhancement. His active involvement in research includes presenting findings at conferences and collaborating with peers to promote progress in physical sciences. In addition to his academic roles,he mentors students,engages in institutional activities,and supports science outreach initiatives. He has also authored research articles in reputed journals such as Transactions on Electrical and Electronic Materials and SPIN .

Srikanta Behera is an Assistant Professor in the Department of Physics at B. J. B. Autonomous College,Bhubaneswar,Odisha,and is also affiliated with the Department of Physics,C.V. Raman Global University Bhubaneswar. He is actively involved in teaching undergraduate and postgraduate physics courses,supervising student research projects,and contributing to academic curriculum development. His research interests span various areas of physical sciences,and he regularly engages in scholarly activities and academic collaborations. He has published research articles in reputed journals,including Transactions on Electrical and Electronic Materials and SPIN . Alongside his academic work,he mentors students and participates in outreach initiatives to promote scientific learning.

Raj Kishore Mishra is currently working as a Reader in Physics at Maharishi College of Natural Law,Bhubaneswar,Odisha,and has more than three decades of teaching experience and over two decades of Research experience. He obtained his PhD in Experimental Condensed Matter Physics from IIT Kharagpur. His research area spans materials science,solid-state physics,dielectrics,ferroelectrics,multiferroelectrics graphene,and energy storage material etc. He has published more than 20 international papers and authored one book chapter Multiferroics-A Multifunctional Material,in the book- Dielectric Materials for Energy Storage and Energy Harvesting Devices (River publishers,international publication). He is presently Secretary of Orissa Physical Society.

Sabyasachi Parida is an Associate professor in physics and currently working in the Department of Physics,C.V. Raman Global University,Bhubaneswar. He is the editor of book Dielectric Materials for Energy Storage and Energy Harvesting Devices . He is the Guest Editor in special issue of Journal Clean Technologies,MDPI . He is the recipient of International Centre for Diffraction Data Certificate award in recognition of the significant contribution of 2 powder diffraction patterns in the Powder Diffraction File. He has handled a DST(India) funded project “Modulation of piezoelectric and electromechanical properties in percolative polymer- ceramic graphene Nano composite for low frequency energy harvester”. He is the author of more than 40 international publications.

Tapan Dash serves as a Principal Scientist at the IGMRC in Bhubaneswar and he has worked as Associate Professor in Physics at the CUTM,Bhubaneswar. He holds a PhD in Physics. With over fifteen years of research experience and a decade of teaching,his areas of expertise encompass nanomaterials research,multiferroic materials,condensed matter physics,nanotubes,the value addition of graphite,the production of graphene,composites,coatings,and the plasma processing of advanced materials,etc. His possesses hands-on experience with a variety of advanced characterization techniques such as X-ray diffraction,X-ray photoelectron spectroscopy,micro Raman,X-ray micro-computed tomography,Brunauer-Emmett-Teller surface area,field emission scanning electron microscopy,transmission electron microscopy,Fourier-transform infrared spectroscopy diffuse reflectance spectroscopy,inductively coupled plasma optical emission spectroscopy,etc. He has published more than 85 research articles,authored a book,and has been granted a patent for his research endeavors.

References

Zeng

Meng

, et al. Enhancing energetic disorder in all-organic composite dielectrics for high-temperature capacitive energy storage. Nat Commun 2025; 16: 5620.

Wang

Hao

Duan

, et al. Energy storage performance with ultrahigh energy density and power density of Ba0.85Ca0.15Zr0.1Ti0.9O₃-based lead-free ceramics through synergistic optimization. Ceram Int 2025; 51: 35133–35143.

Haertling

. Ferroelectric ceramics: history and technology. J Am Ceram Soc 1999; 82: 797–818.

Weston

Cui

Ringer

, et al. Multiferroic crossover in perovskite oxides. Phys Rev B 2016; 93: 165210.

Raji

Ramachandran

Muralidharan

, et al.

Dual-phase formation in LaFeO₃ upon doping of rare-earth Dy³⁺: struct–opto–dielectric–magnetic characteristics.

J Mater Sci Mater Electron 2022; 33: 10626–10644.

Ramesh Kumar

Ramachandran

Natarajan

, et al.

Fraction of rare-earth (Sm/Nd)-lanthanum ferrite-based perovskite ferroelectric and magnetic nanopowders.

J Electron Mater 2019; 48: 1694–1703.

Raji

Ramachandran

Hamed

, et al.

Tailoring multiferroic characteristics in LaFeO₃ nanocrystals via rare-earth Pr³⁺ doping.

Adv Condens Matter Phys 2023; 1: 7369790.

Raji

Ramachandran

Muralidharan

, et al.

Twitching the inherent properties: the impact of transition metal Mn-doped on LaFeO₃-based perovskite materials.

J Mater Sci Mater Electron 2021; 32: 25528–25544.

Raji

Ramachandran

Muralidharan

, et al.

Conventional synthesis of perovskite structured LaTixFe1-xO₃: a comprehensive evaluation on phase formation, opto-magnetic, and dielectric properties.

Int J Mater Res 2021; 112: 753–765.

10.

Acosta

Novak

Rojas

, et al. BaTiO₃-based Piezoelectrics: fundamentals, current status, and perspectives. Appl Phys Rev 2017; 4: 041305-1-53.

11.

Hill

. Why are there so few magnetic ferroelectrics? J Phys Chem B 2000; 104: 6694–6709.

12.

Spaldin

Fiebig

. The renaissance of magneto electric multiferroics. Science 2005; 309: 391–392.

13.

Eerenstein

Mathur

Scott

. Multiferroic and magnetoelectric materials. Nature 2006; 442: 759–765.

14.

Jiangtao

Shaoyu

Zuo-Guang

, et al. Room-temperature ferromagnetic/ferroelectric BiFeO₃ synthesized by a self-catalyzed fast reaction process. J Mater Chem 2010; 20: 6512–6516.

15.

Mishra

Pradhan

Choudhary

RNP

, et al. Effect of yttrium on improvement of dielectric properties and magnetic switching behavior in BiFeO₃. J Phys Condens Matter 2008; 20: 045218.

16.

Liu

Xiang

Cheng

, et al. Multiferroic and magnetodielectric effects in multiferroic Pr₂FeAlO₆ double perovskite. Nanomaterials 2022; 12: 3011.

17.

Mishra

Choudhary

RNP

Banerjee

. Bulk permittivity, low frequency relaxation and the magnetic properties of Pb(Fe_1/2Nb_1/2)O₃ ceramics. J Phys Condens Matter 2010; 22: 025901-8.

18.

Raevski

Prosandeev

Bogatin

, et al.

High dielectric permittivity in AFe1/2B1/2O3 nonferroelectric perovskite ceramics (a=ba, sr, ca; b=nb, ta, sb).

J Appl Phys 2003; 93: 4130–4136.

19.

Tezuka

Henmi

Hinatsu

, et al.

Magnetic susceptibilities and mössbauer spectra of perovskites A2FeNbO₆ (A=Sr, Ba).

J Solid State Chem 2000; 154: 591–597.

20.

Saha

Sinha

. Dielectric relaxation in SrFe_1∕2Nb_1∕2O₃. J Appl Phys 2006; 99. doi:10.1063/1.2160712

21.

Wang

Chen

, et al.

Dielectric abnormities of complex perovskite Ba (Fe_1∕2Nb_{1 2})O₃ ceramics over broad temperature and frequency range.

Appl Phys Lett 2007; 90.

22.

Wang

Chen

, et al.

Dielectric relaxations in Ba (Fe_1∕2Ta_1∕2)O₃ giant dielectric constant ceramics.

Appl Phys Lett 2007; 90: 102905 .

23.

Dhilip

Punitha

Rameshkumar

, et al.

A novel double perovskite oxide Sm₂CoFeO₆ phosphor for orange LEDs: structural, magnetic and luminescence properties.

Appl Phys A 2022; 128: 24.

24.

Pascual-Gonzalez

Schileo

Murakami

, et al. Continuously controllable optical band gap in orthorhombic ferroelectric KNbO₃-BiFeO₃ ceramics. Appl Phys Lett 2017; 110: 172902.

25.

Biedermann

Speziale

Winkler

, et al. High-pressure phase behavior of SrCO 3: an experimental and computational Raman scattering study. Phys Chem Minerals 2017; 44: 335–343.

26.

Hota

Panda

Bhoobash

, et al. Polyvinylidene fluoride–barium tungstate nanocomposite for advanced energy storage devices. Polym Bull 2025; 82: 7319–7342.

27.

Hota

Panda

, et al. Dielectric characteristics and energy storage capabilities of PVDF-based composite incorporating 2D GnP nanofiller. Results Eng 2025; 26: 105593.

28.

Liu

Duan

, et al. Two-channel whispering gallery mode self-injection locking lasers for hybrid optically pumped atomic comagnetometers. Measurement ( Mahwah N J) 2025; 246: 116674.

29.

Yang

Lin

Meng

, et al. Relaxor antiferroelectric dynamics for neuromorphic computing. Adv Mater 2025; 37: 2419204.

30.

Zhang

Fang

. High dielectric constant and dielectric relaxations in La_2/3Cu₃Ti₄O₁₂ ceramics. Materials (Basel) 2022; 15: 4526.

31.

Qian

Chen

Luo

, et al. Electric current-induced directional slip of dislocation and grain boundary ordering. Mater Today Adv 2024; 24: 100530.

32.

Wang

Liu

, et al. Alternating multilayered Ti₃C₂Tx/Co sandwich with co frosting for superior electromagnetic wave absorption performance and infrared stealth ability. ACS Appl Mater Interfaces 2025; 17: 47679–47695.

33.

Wang

Huo

, et al. Universal core–shell nanowire memristor platform with quasi-2D filament confinement for scalable neuromorphic applications. Adv Funct Mater 2025; e18764. doi: https://doi.org/10.1002/adfm.202518764

34.

Phatungthane

Jaita

Sanjoom

, et al. Dielectric properties of Sr1-xBaxFe0. 5Nb0. 5O₃;(x= 0.0, 0.1 and 0.2) ceramics prepared by the molten salt technique and their electrode effects. Surf Coat Technol 2016; 306: 229–235. doi:10.1016/j.surfcoat.2016.06.004

35.

Huo

Meng

, et al. Negative differential resistance with ultralow peak-to-valley voltage difference in td-WTe2/2H-MoS2 heterostructure. Nano Lett 2024; 24: 11937–11943.

36.

Jonscher

. A new understanding of the dielectric relaxation of solids. J Mater Sci 1981; 16: 2037–2060.

37.

Khelifi

Zouaria

Al-Hajryc

, et al. Ac conductivity and ferroelectric phase transition of Bi_0.7(Ba_0.8Sr_0.2)_0.3Fe_0.7Ti_0.3O₃ ceramic. Ceram Int 2015; 41: 12958–12966.

38.

Sanjoom

Jaita

Chokethawai

, et al. Colossal dielectric constants in sr(Fe_0.5Nb_0.5)_1−xMn_xO₃ prepared by a modified solid-state reaction technique. Ferroelectrics 2022; 601: 9–23.

39.

Lazanas

Prodromidis

. Electrochemical impedance spectroscopy─a tutorial. ACS Measurement Science Au 2023; 3: 162–193.

40.

Zhang

Han

, et al. Reversible manipulation of field-free perpendicular magnetization switching via electric field. Appl Phys Lett 2025; 126: 172401.

41.

Zhao

Liu

, et al. Modeling and suppression of magnetic noise in nanocrystalline magnetic shielding system considering residual loss magnetic noise and interlayer effects. Measurement ( Mahwah N J) 2025; 250: 117216.

42.

Wang

Liu

, et al. Theoretical modeling and characterization of equivalent magnetic properties in laminated composite magnetic shielding. Measurement ( Mahwah N J) 2025; 251: 117237.

43.

Yáñez-Vilar

Mun

Zapf

, et al. Multiferroic behavior in the new double-perovskite Lu₂MnCoO₆. Phys Rev B 2011; 84: 134427.

44.

Lu1

Lin

, et al. Single-phase multiferroics: new materials, phenomena, and physics. Natl Sci Rev 2019; 6: 653–668.

Dipolar and magnetic order in Sr(Mn 1/2 Nb 1/2 )O 3

Abstract

Keywords

Introduction

Experiment

Results and discussion

XRD study

Raman study

Dielectric and electrical properties

Impedance study

Conductivity study

Nyquist plot study

Magnetic properties

Conclusion

Footnotes

Acknowledgement

ORCID iD

Ethical considerations

Author contributions

Funding

Declaration of conflicting interests

Author biographies

References