Electronic, optical, magnetocaloric, and thermoelectric properties of La_0.5Sm_0.2Sr_0.3MnO₃: a first-principles DFT-MFT investigation

Abstract

Density functional theory (DFT + U) and mean-field theory (MFT) calculations were carried out on La₀.₅Sm₀.₂Sr₀.₃MnO₃ to investigate its electronic, magnetic, and optical properties using the Wien2k package. The total density of states and band structure indicate a semi-metallic ferromagnetic nature. Magnetic properties analyzed with MFT reproduced magnetization isotherms and magnetic entropy (−ΔS) curves, consistent with ferromagnetic behavior. The good agreement between experiment and simulation highlights the reliability of the employed model in predicting the magnetocaloric properties of La₀.₅Sm₀.₂Sr₀.₃MnO₃. Optical parameters, including dielectric constants ε₁(ω) and ε₂(ω), absorption coefficient α(ω), and optical conductivity, were studied over 0–14 eV. The Seebeck coefficient (S) decreases with temperature, and its positive sign confirms hole conduction. The figure of merit attains a maximum ZT = 1.22 at 200 K.

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1 Introduction

Perovskite manganites have attracted extensive attention due to their fascinating multifunctional properties and wide range of technological applications.^1–5 Among these, LaMnO₃ is particularly important because of its ferroelectric behavior, high dielectric constant, spontaneous polarization, and nonlinear optical properties.^6–8 This material is used in many different devices, including multilayer ceramic capacitors,^9,10 bolometers,¹¹ and infrared detectors. Furthermore, La-based manganites stand out within the perovskite family due to their rich interplay of structural, electronic, and magnetic degrees of freedom, which can be finely tuned by chemical substitution or external stimuli. Doping in LaMnO₃ plays a crucial role in tailoring its physical behavior. The parent compound shows antiferromagnetic ordering at low temperature, whereas substitution with divalent cations (e.g., Sr²⁺, Ca²⁺, or Ba²⁺) induces mixed-valence states of Mn, promoting double-exchange interactions that can drive the system into ferromagnetic and metallic states. Loshkareva et al.¹² investigated the effects of light n- and p-type doping on the optical spectra of LaMnO₃ and reported substantial modifications in electronic structure, including shifts in absorption edges and additional absorption features. Importantly, both doping types led to electronic phase separation, highlighting the complex interplay between charge, orbital, and spin degrees of freedom in this system.

Beyond magnetism and electronic transport, LaMnO₃ exhibits promising thermoelectric properties, with a positive Seebeck coefficient indicating predominant p-type behavior.^3,13 Although its dimensionless figure of merit (ZT) is moderate (0.1–0.3), structural engineering and cation substitution have been suggested as effective strategies to enhance thermoelectric efficiency. Simultaneously, the compound displays complex magnetic transitions between antiferromagnetic and ferromagnetic states, making it a candidate for magnetocaloric applications.

Theoretical approaches (e.g. density functional theory (DFT) and the Bean–Rodbell) are considered fundamental pillars of materials science. DFT is particularly valuable because it enables accurate prediction of material properties at the atomic scale using quantum mechanics. It provides insight into electronic structure, magnetism, and thermal behavior without relying solely on costly experiments. Moreover, DFT supports the design of advanced materials for applications in semiconductors, batteries, and solar cells, making it an indispensable tool for both research and industrial innovation. In parallel, the mean field theory plays a key role in describing magnetic phase transitions in systems where magnetism is strongly coupled with structural changes. By incorporating the effect of cationic disorder, this model offers a reliable framework for predicting the magnetocaloric effect. Sclauzero et al. combined density functional theory (DFT) with dynamical mean-field theory (DMFT) to investigate the impact of epitaxial strain on the structural and electronic properties of LaVO₃.¹⁴ More recently, methodological advances in DFT combined with DMFT have enabled a rigorous analysis of electron–electron scattering in correlated materials such as SrVO₃, SrMoO₃, and SrRuO₃.¹⁵ In addition, Arejdal et al. employed a hybrid approach that integrates ab initio calculations with Monte Carlo simulations (MCS) and the mean-field approximation to study the magnetic properties of the double perovskite Ba₂CoUO₆.¹⁶ While numerous studies have investigated the physical properties of simple perovskites using theoretical approaches such as density functional theory (DFT) and mean-field theory, comparatively fewer works have examined highly mixed systems. Within the LaMnO₃ family, mixed perovskite oxides such as La₀.₅Sm₀.₂Sr₀.₃MnO₃ are of particular interest. In this compound, the A-site is occupied by a mixture of large cations (La³⁺, Sm³⁺, and Sr²⁺), while Mn occupies the B-site. Partial substitution of La and Sm with Sr modifies the Mn–O–Mn bond geometry, thereby influencing double–exchange interactions and tuning both the transport and magnetic properties. Notably, La₀.₅Sm₀.₂Sr₀.₃MnO₃ exhibits colossal magnetoresistance (CMR) and undergoes a second-order paramagnetic-to-ferromagnetic transition with a Curie temperature of about 278 K,¹⁷ making it a promising candidate for spintronic devices and room-temperature sensing applications.

Despite the large number of studies on LaMnO₃-based systems, the fundamental electronic, optical, magnetocaloric, and thermoelectric properties of La₀.₅Sm₀.₂Sr₀.₃MnO₃ have not yet been systematically explored using first-principles calculations combined with mean-field theory. In this work, we address this gap by employing density functional theory (DFT) together with MFT simulations to provide deeper insight into the intrinsic properties of this compound. Our study not only clarifies the microscopic mechanisms governing its multifunctional behavior but also contributes to the rational design of manganite-based materials for energy conversion and magnetic cooling applications.

2 Experimental details

The glycine-nitrate process (GNP) was used to synthesize the La_0.5Sm_0.2Sr_0.3MnO₃ sample. High purity glycine (C₂H₅NO₂, 99.9%) and stoichiometric amounts of La (NO₃)₃·6H₂O, Sm (NO₃)₃·6H₂O, Sr (NO₃)₂, Mn (NO₃)₂·4H₂O, and Fe (NO₃)₃·9H₂O (each with a purity of least 99.995%) were used in a 1 : 1 molar ratio. All the nitrates were dissolved in distilled water. This solution was heated to 100 °C under magnetic stirring for additional hour. The temperature slowly increased until the solution evaporated and transformed into a clear, viscous gel. The autoignition process began when a crucial temperature of 350 °C was reached. A foam powder was obtained. This powder was ground and calcined to completely eliminate organic residues, yielding the final product.

Phase purity was evaluated using a Phillips powder diffractometer. The analysis was performed with CuKα radiation (λ = 1.5406 Å) and employed systematic scans that operated at a step size of 0.017° across an angular within the range of 10° ≤ 2θ ≤ 100°. The XRD data were analyzed using the FullProf program based on the Rietveld method.¹⁸

3 Theoretical considerations

3.1 Ab initio calculation details

To explore the electronic properties and to clearly understand the origin of the magnetic and optical properties of the compound La_0.5Sm_0.2Sr_0.3MnO₃, a DFT + U calculation was performed using the WIEN2k simulation package.¹⁹ We adopted the structural parameters from our previous study¹⁷ to create a 1 × 1 × 5 supercell containing 10 atoms of La, 6 atoms Sr, 4 atoms of Sm, 20 atoms of Mn, and 60 oxygen atoms. To investigate the electronic properties and to clearly understand the origins of the magnetic and optical properties of this compound, DFT calculations were investigated. To improve the accuracy of the electronic structures of these perovskites while remaining within the DFT framework, it is possible to introduce an in-site Hubbard parameter (GGA + U), adjusted according to the convergence of the total energy. An appropriate value of U_eff (U = U_eff − J) allows to take into account the Coulomb interactions between the Sm 4f and Mn 3d electrons.²⁰ The values of U used in this work were 7 eV and 4 eV for the Sm²¹ and Mn²⁰ ions, respectively. To ensure proper convergence for all calculations, the cutoff energy defined as the separation energy between valence and core states was set to −7 Ry (∼−95.24 eV), and the number of k-points was set to 2000. The muffin-tin radii (RMT) for La, Sm, Sr, Mn and O atoms were 2.5, 2.4, 2.3, 1.87, and 1.61 a.u., respectively. The plane-wave energy cutoff parameter RMT × KMAX was set to 8.0. The structure was optimized and fully relaxed. The convergence conditions adopted were as follows: the energy variation and the force difference were set to 10⁻³ eV and 10⁻² eV Å⁻¹, respectively.

The thermoelectric properties were calculated using the Boltzmann transport theory as implemented in the BoltzTrap code.²² The values of σ and κ are dependent on the relaxation time (τ), which was treated as a constant (τ = 10⁻¹⁴ s) within the BoltzTrap code.

3.2 Mean-field theory (MFT)

The Brillouin equation was used to model the magnetization of a magnetic material:^23,24where M₀ = NJgμ_B represents the saturation magnetization and B_j(x) represents the Brillouin function and expressed as follow:where is angular momentum. The orbital and spin momentums (L and S) were linked by Lande factor .

In the MFT context, the exchange field H_exch is linked to magnetization by this relation:

In addition, the magnetic entropy change (ΔS_M) can be simulated by the following form:

The order of the magnetic transition is related by the compressibility K, the total momentum J, and spin density N by the following equation:²⁴

With k_B is the Boltzmann constant.

The first-order magnetic transition in a material can be defined by η > 1 value, while η < 1 denotes a second order transition.²⁵

4 Results

4.1 Structural properties

The refined X-ray diffraction (XRD) pattern of the compound La_0.5Sm_0.2Sr_0.3MnO₃ (Fig. 1) exhibits sharp and intense peaks indicating the formation of a well-defined crystal structure with no detectable secondary phases. All peaks in the refined profile can be indexed to an orthorhombic unit cell (space group Pnma). The crystallographic parameters, including lattice constants (a, b and c), Mn–O bond lengths, Mn–O–Mn bond angles and the reliability factors of the Rietveld refinement, are summarized in Table 1. The goodness of fit was assessed using the R factors and the χ² parameter, which indicated excellent agreement between the experimental and calculated patterns.

Fig. 1 Rietveld-refined X-ray diffraction patterns of La_0.5Sm_0.2Sr_0.3MnO₃ sample: the calculated data is depicted as solid black line, the observed data appeared as red dots, the Bragg reflection positions are represented by green ticks, and the blue line demonstrates the difference between the calculated and observed data.

Table 1 Structural parameters obtained from Rietveld refinement

Space group		Pnma
Cell parameters
Experimental parameters	a (Å)	5.501
	b (Å)	7.732
	c (Å)	5.469
	V (Å^3)	232.686
Optimized parameters (DFT + U)	a (Å)	5.4762
	b (Å)	7.7573
	c (Å)	5.4867

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Agreement factors
Rp (%)	3.32
RWP (%)	4.21
Rexp (%)	3.67
Bragg R-factor(%)	1.83
RF-factor (%)	3.86
χ^2	1.31
Bond lengths
Mn–O1 (Å)	1.939
Mn–O2 (Å)	2.113
Mn–O2 (Å)	1.823
Bond angles
Mn–O1–Mn	170.62
Mn–O2–Mn	162.412

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To understand the principles governing the formation and structural stability of perovskite oxide systems, Goldschmidt introduced the tolerance factor (t_G) as an empirical parameter. This parameter depends on the ionic radii of the A- and B-site cations and the oxygen anion, as well as the degree of octahedral distortion. It is expressed as:

where r_A represents the average ionic radius of the A-site cations (La, Sm, Sr), r_B is the radius of the B-site cation (Mn), and r_O corresponds to the oxygen anion. For perovskite systems, structural stability is generally achieved within the range 0.75 < t_G < 1, with maximum symmetry obtained as t_G approaches unity.

Using Shannon's tabulated ionic radii, the tolerance factor of La_0.5Sm_0.2Sr_0.3MnO₃ was calculated to be t_G = 0.92, supporting that the orthorhombic crystal structure is stable. In addition, the average crystallite size (D) was estimated from the Debye–Scherrer equation:

where λ is the Cu Kα radiation wavelength, K is the Scherrer constant (0.9), β is the full width at half maximum (FWHM) of the diffraction peak in radians, and θ is the Bragg angle. The calculated crystallite size confirms the nanocrystalline nature of the compound.

4.2 Electronic properties

To study the electronic properties of La_0.5Sm_0.2Sr_0.3MnO₃ compound, total electronic density of states (TDOS) is shown in Fig. 2a. The density of states (DOS) for the spin-down channel does not drop to zero at the Fermi level (E_F), indicating the presence of electronic states available at E_F. This availability allows for electrical conduction in the spin-down channel, exhibiting metallic behavior. In contrast, the spin-up channel shows a band gap, revealing half-metallic behavior of the studied material. Additionally, the TDOS plot shows different distributions for spin-up and spin-down electrons. This asymmetry indicates the ferromagnetic nature of the compound with a calculated total magnetic moment ∼3 μ_B.

Fig. 2 (a) Total density of states for La_0.5Sm_0.2Sr_0.3MnO₃, (b–f) partial density of states of La, Mn 3d, Sm and O.

Fig. 2b–f shows that below −1 eV, the electron energy states are composed of Sr 4p, Mn 3d, and O 2p states. Above ∼3 eV, they are mainly contributed by Sr 3d states, while near 4 eV, La and Sm 4f states dominate.

Remarkably, near the Fermi energy (E_F) level, for spin-down, the energy states are primarily composed of Mn 3d, Sm 4f and O 2p. The strong hybridization, at E_F level, between these orbitals indicates enhanced covalent interaction between Mn/Sm, and O ions which contribute to the observed metallic behavior.

The transport mechanism in manganite materials is known to be primarily influenced by electrons situated in the Mn 3d and O 2p orbitals.^20,26 It is well established that the MnO₆ octahedra are deformed due to the presence of a Jahn–Teller type distortion, which also divides the degenerate states of the eg orbital into x²–y² and 3z² states, and the 2t_g orbital into 3d_xy, 3d_xz, and 3d_yz. Near the Fermi level, the majority of energy states in the valence band are occupied by Mn: d_yz, d_xz, d_xy and O 2p, while the conducted band is occupied by the Mn 3d_z², x²–y², and 3d_xy orbitals. For the spin up states, the 3d_z² orbital is lowered in energy due to compressive stress. Consequently, a band gap develops as valence electrons prefer to occupy the lower energy orbital under these constraints.²⁷

Fig. 3 depicts the “spin up and spin down” band structure. The valence states in the spin down cross the Fermi level showing that the free carriers are available to exhibit a metallic character, while in the spin up scenario a semiconducting behavior with a band gap E_g = 1.9 eV is observed. Therefore, the overall behavior of the studied compound is half-metallic. By comparing the band structure with the computed DOS, the band gap value can be attributed to the electron density states for Sm 4f, Mn 3d, and O 2p.

Fig. 3 Band structure (spin up (a) and down (b)) for La_0.5Sm_0.2Sr_0.3MnO₃ sample.

4.3 Optical properties

The optical properties of the La_0.5Sm_0.2Sr_0.3MnO₃ sample were investigated using the Kramers–Kronig relation. In the field of linear optics, the dielectric functions ε₁ and ε₂ are used to characterize the main optical properties.^28,29 The frequency-dependent dielectric function ε(ω), can be expressed as:

ε(ω) = ε₁(ω) + iε₂(ω) (8)

where ε₁(ω) and ε₂(ω) are known to be the real part and imaginary part of the complex dielectric function (Fig. 4).

Fig. 4 Optical properties: (a) the real dielectric constants ε₁(ω), (b) the imaginary dielectric constants ε₂(ω), (c) the absorption coefficient α(ω), and (d) real part of optical conductivity le long de [100] et [010] directions cristallographiques qui sont représentées respectivement par les directions xx et yy.

It is shown that the static real dielectric constant ε₁(0) exhibits a large value (ε₁(0) = 19.27 eV), which corresponds to the plasmon resonance.³⁰ As the energy photon increases, ε₁(ω) decreases sharply reaching a minimum at 0.32 eV which may be related to the metallic character for the spin down states and the ferroelectric nature of the perovskite.²⁷ Above E = 9 eV, ε₁(ω) becomes negative indicating that incident radiation is completely reflected by the surface.^29,31 Fig. 3b shows the variation of ε₂(ω) as function of photon energy. Four dielectric peaks E₁, E₂, E₃, and E₄ were observed which agree with the photon energy 1.4 eV, 3.2 eV, 5.8 eV, and 7.6 eV. These peaks are mainly due to electric–dipole transitions between the valence and conduction bands.³²

According to DOS, the E₁, E₂ dielectric peaks are associated with the electronic transition between the top of the valence band and the bottom of the conduction band, mainly arising from Mn-3d and O-2p orbitals. However, the other peaks originate mainly from the electronic transition between the La-p, Sm 4f, Sr 3p, and O 2s orbitals.

The high absorption in the UV-A range suggest that this material can be used as an absorber in solar cell and other optoelectronic applications.³¹

The optical absorption spectrum shows slightly anisotropic, with the strongest absorption along the y-polarization occurring at 8.5 eV, while the strongest absorption along the c-axis occurs at 10 eV.

4.4 Magnetic properties

The magnetic and magnetocaloric properties of the La_0.5Sm_0.2Sr_0.3MnO₃ sample were studied in our previous work.¹⁷ The study showed that the present compound exhibits a second order magnetic transition from ferromagnetic state FM to a paramagnetic state PM at T_C = 278 K.¹⁷

Fig. 5 displays the magnetic hysteresis measured at 5 K under a magnetic field range up to 2 T. The graph shows a typical S-shaped ferromagnetic loop, where magnetization increases rapidly with the applied magnetic field, then saturates at higher fields.

Fig. 5 Magnetic hysteresis measured at 5 K under a magnetic field reaches 2 T.

In order to quantify the magnetic parameters saturation magnetization M_s, intrinsic coercivity H_c, and remnant magnetization M_r, the M−H loop was fitted using the following equation:³³

The first term quantifies the FM contributions while the second represents AFM contribution (linear contributions).

The green line (AFM contribution) is nearly zero across the range of the applied magnetic field, suggesting that any antiferromagnetic component is negligible in this material. The saturation magnetization M_s (emu g⁻¹) and the molecular weight MW (g mol⁻¹) are used to calculate the magnetic momentsμ_fu (μ_B) according to the following relation.^33,34

where μ_B is the Bohr magneton and N_A = 6.022× 10²³ mol⁻¹ is the Avogadro's number. The magnetic parameters extracted from hysteresis (Fig. 5) fitting are summarized in Table 2. It is noticed that the M_r/M_s value is close to 0.5 which presents the theoretical value for randomly oriented single-domain particles.³³

Table 2 Magnetic parameters for La_0.5Sm_0.2Sr_0.3MnO₃ obtained from the hysteresis loops fitting

	Total	AFM contribution	FM contribution				%
	μfn (μB) 5 K	χ	HC (10^−4 T)	M^SFM (emu g^−1)	M^RFM (emu g^−1)	MR/MS	FM	AFM
La0.5Sm0.2Sr0.3MnO3	3.5	4.608	875	75	30	0.4	93.75	6.25

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Amaral et al. have developed a good method based on MFT to simulate the magnetization isotherms and −ΔS curves.^23,35 This approach employs eqn (1) to modify the scaling plot curves of magnetization (M vs. ) in order to obtain the total momentum J and the saturation magnetization M_s.

To ascertain the H_exch values, the fluctuation of were plotted in Fig. 5, using a constant magnetization value of 5 emu g⁻¹.

Following eqn (4), the H_exch values can be determined from the slope of each curve by applying a linear fit in the PM region. The variation of H_exch as a function of magnetization M, modified by the following equation, is shown in Fig. 6.

H_exch = λ₁M + λ₃M³ (11)

Fig. 6 Variation of H/T vs. 1/T curves with constant values of magnetization for the La_0.5Sm_0.2Sr_0.3MnO₃ sample.

It is found that the values of λ₁ and λ₃ are, respectively, 1.5137 and −1.1456 × 10⁻⁴ T g³ emu⁻³. As opposed to λ₃, the value of λ₁ is significantly high. Consequently, λ₃ is neglected. Thus, the exchange field can be written as follows (Fig. 7).

H_exch = λ₁M ≈ λM (12)

Fig. 7 Exchange field dependence of magnetization for the La_0.5Sm_0.2Sr_0.3MnO₃ sample. Red line as the fit by the equation H_exch = λ₁M + λ₃M³.

M vs. (H + H_exch)/T is plotted in Fig. 8 using a scaling plot. All magnetization isotherms are reduced to a single curve, which has been modified in MATLAB software by adjusting eqn (1) in order to extract the experimental values of M_S, J, and g.²³ Table 3 provides a summary of the acquired values.

Fig. 8 Scaled data in magnetization vs. (H + H_exch)/T and the Brillouin function fit for the La_0.5Sm_0.2Sr_0.3MnO₃ compound.

Table 3 The extracted M_S, J, g, λ and, η parameters

Sample	J	g	Ms (emu g^−1)	T0 (K)	λ	η
La0.5Sm0.2Sr0.3MnO3	3.2	2.3	79	277.5	1.5137	0.4

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The extracted M_S, J, and g values listed in Table 3 are utilized to modulate the M (H, T) and −ΔS_M curves as illustrated in Fig. 9a and b. These curves are generated using the Magnetocaloric Software Suite (MFSS) running MATLAB.

Fig. 9 (a) Experimental (symbols) and simulated (red lines) magnetization M vs. μ₀H. (b) Experimental (symbol) and theoretical (red line) magnetic entropy change versus temperature under different magnetic fields.

The good agreement between the experimental and simulated curves proves the pertinence of the employed model for the prediction of La_0.5Sm_0.2Sr_0.3MnO₃ magnetocaloric properties.

4.5 Thermoelectric properties

By analyzing the band structures of a material, one can estimate its transport properties using the semi-classical Boltzmann transport theory.³⁶ The following equations can be implemented to calculate the Seebeck coefficient, electrical conductivity, and thermal conductivity.³

S_αβ(T,μ) = σ_αβ(T,μ)⁻¹ϑ_αβ(T,μ) (15)

Fig. 10 illustrates the temperature dependence of the electrical conductivity and thermal conductivity, total Seebeck coefficient, and ZT factor for the La_0.5Sm_0.2Sr_0.3MnO₃. As depicted in Fig. 10a, the electrical conductivity for spin-up states exhibits typical behavior of a semiconductor. In this scenario, the conductivity remains constant at low temperatures and experiences an exponential increase at the high-temperature range. This is attributed to the fact that free carrier charges possess higher energy to overcome the potential barrier at elevated temperatures.

Fig. 10 (a) Variation of electron conductivity, (b) thermal conductivity, (c) total Seebeck coefficient, and (d) ZT factor.

The electrical conductivity for spin-down states demonstrates a consistent decline with rising temperature, indicative of metallic behavior. The variations in thermal conductivity as a function of temperature for the spin-up and spin-down states are shown in Fig. 10b.

The total electronic thermal, electrical conductivity, and Seebeck coefficients are given by = k(↑) + k(↓), σ = σ(↑) + σ(↓) and where (↑) and (↓) represent the coefficients for spin up and spin down, respectively. Utilizing this model, the total Seebeck coefficient (Fig. 10c) obtained shows a decrease as temperature increases. A positive Seebeck coefficient (S) indicates that holes contribution predominantly governs electric conduction.³⁷

Fig. 10d depicts the evolution of the ZT figure of merit as a function of temperature (T). Similar to the Seebeck coefficient, ZT attains the maximum of ZT = 1.22, at low temperature 200 K decreasing while maintaining a value above 0.8. The ZT value reaches 1.2 at 300 K, indicating that the material can be considered a viable option for thermoelectric device integration.

Comparing the thermoelectric and magnetocaloric properties of La₀.₅Sm₀.₂Sr₀.₃MnO₃ with other similar perovskite-based manganite compounds provides a broader perspective on its performance. For example, Li et al. reported a complex structure in SrTiO₃, with a TiO₂ secondary phase and a porous morphology. This microstructural design led to an enhanced thermoelectric performance, achieving a ZT value of 0.31 at 1050 K First-principles calculations and high thermoelectric performance of La-Nb doped SrTiO₃ ceramics.³⁸ Sr_0.75Ca_0.25Mn_0.95V_0.05O_3−δ material has shown high values of dimensionless figure-of-merit high-temperature thermoelectrical properties of cubic SrMnO_3−δ based manganites.³⁹ A maximum value of 0.09 for the figure of merit (ZT) is obtained for 0.95 LaCoO₃–0.05La_0.7Sr_0.3MnO₃ at 620 K which is significantly higher than the ZT of either of LaCoO₃ or La_0.7Sr_0.3MnO₃ at 620 K.⁴⁰

In contrast, La₀.₅Sm₀.₂Sr₀.₃MnO₃ exhibits a higher figure of merit with ZT reaching 1.22, which can be attributed to the optimized electronic structure resulting from Sm and Sr substitution at the La site.⁴¹

This comparative analysis confirms that La₀.₅Sm₀.₂Sr₀.₃MnO₃ exhibits enhanced multifunctional properties, making it a strong candidate for applications in magnetic refrigeration and thermoelectric energy conversion devices.

5 Conclusion

The La_0.5Sm_0.2Sr_0.3MnO₃ compound was successfully synthesized using the glycine-nitrate procedure GNP. DFT and MFT theoretical approaches have led to a better understanding of the electronic, magnetic, optical and thermoelectric properties of this material. Electronic structure analysis revealed that La_0.5Sm_0.2Sr_0.3MnO₃ exhibits semi-metallic behavior, with strong covalent interactions between Mn, Sm and O ions contributing to its metallic characteristics. The compound also displays notable ferromagnetic behavior, with a second-order magnetic transition from the ferromagnetic to the paramagnetic state at 278 K. In addition, the optical properties indicate potential applications in solar cells and optoelectronic devices, due to the high absorption of the material in the UV-A range. Finally, the thermoelectric analysis demonstrated that La_0.5Sm_0.2Sr_0.3MnO₃ is promising for the integration of thermoelectric devices, with a ZT value reaching 1.22 at 200 K. These findings highlight the versatility of La₀.₅Sm₀.₂Sr₀.₃MnO₃, making it a promising material for applications in electronics, magnetism, optics, and thermoelectricity.

Author contributions

A. Mabrouki: writing, performed DFT calculations. Khouloud Abdouli: writing, methodology, validation. Afrah Bardaoui: conceptualization, methodology, validation. O. Messaoudi: investigation, visualization, writing, original draft preparation. Latifah Alfhaid: writing, conceptualization, methodology, validation. Amjad S. Aljaloud: supervisor, methodology, validation.

Conflicts of interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Data availability

No primary research results, sotware or code have been included and no new data were generated or analysed as part of this review.

Acknowledgements

This research has been funded by the Research Deanship of the University of Ha'il-Saudi Arabia through Project Number RG-23 135.

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