Structural and electrical properties of calcium substituted lanthanum ferrite powders

Andoulsi, Refka; Horchani−Naifer, Karima; Férid, Mokhtar

doi:10.1016/j.powtec.2012.07.026

Cited by 51 publications

(17 citation statements)

References 24 publications

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“…The Ca doping consequently decreased the cell volume of La 1-x Ca x FeO 3 , although to slight extent. [15][16][17] In addition, La 3+ ion was replaced partially by the lower state Ca 2+ ion so as to maintain charge neutrality of the entire compound. Subsequently, the perovskite structure either produced an Fe 4+ ion, which is a B-site element having higher valence state, or an oxygen hole.…”

Section: Xrd Analysismentioning

confidence: 99%

The influence of Ca substitution on LaFeO₃ nanoparticles in terms of structural and magnetic properties

Lin

Yang

et al. 2018

Journal of Applied Biomaterials & Functional Materials

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Background: The nanocrystalline structure of La 1-x Ca x FeO 3 was prepared by a sol-gel method involving an autocombustion process. The incorporation of rare-earths in LaFeO 3 induces strain in magnetic properties, especially in terms of the following parameters: replacement amount, oxygen partial pressure, and calcination temperature. Methods: To determine the effects of the amount of Ca 2+ ion doping agent and the calcination temperature on the microstructure, particle morphology, and magnetic properties of LaFeO 3 crystal, we performed the following respective analytical methods: X-ray powder diffraction, Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy, and vibrating sample magnetometer tests. Results: The orthorhombic structure of LaFeO 3 perovskite did not change even when it was doped with Ca 2+ ions, and its space group continued to be Pnma (No.62). FT-IR spectra confirmed that the main band appearing at 568 cm −1 is due to the antisymmetric stretching vibration of Fe-O-Fe bonds in FeO 6 . The introduction of Ca inhibits the growth of grains but the morphology of particles is improved. With an increasing concentration of Ca 2+ ions, magnetic behavior of the samples also witnessed an increasing trend in a proportionate manner. With an increase in calcination temperature, the enclosed area of the magnetic hysteresis curve of the sample reduced remarkably. Conclusions: The growth of nanoparticles can be restrained with an increase of Ca content that is used as doping agent. The magnetic behavior of La 1-x Ca x FeO 3 tilts towards G-type antiferromagnetism; the magnetic orientation is achieved from the super exchange interaction of Fe 3+ ions with oxygen ions.

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Section: Xrd Analysismentioning

confidence: 99%

The influence of Ca substitution on LaFeO₃ nanoparticles in terms of structural and magnetic properties

Lin

Yang

et al. 2018

Journal of Applied Biomaterials & Functional Materials

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“…However, their dielectric properties have been less investigated. In our previous work, we studied the structural and electrical properties of La 1-x Ca x FeO 3-δ (0 ≤ x ≤ 0.5) compounds and determined motivating results [19,20]. Of particular note, the direct current conductivity optimal value was registered for the 20% substituted amount.…”

Section: Introductionmentioning

confidence: 98%

Dielectric properties of calcium-substituted lanthanum ferrite

Andoulsi-Fezei

Sdiri

Horchani−Naifer

et al. 2020

Journal of Asian Ceramic Societies

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Among La 1-x Ca x FeO 3-δ (0 ≤ x ≤ 0.5) compounds, the optimal value of the direct current conductivity was registered for a 20% substituted amount. We therefore attempted to study the impedance and dielectric properties of 20% calcium-substituted lanthanum ferrite. We investigated the electric properties in depth between 5 Hz and 13 MHz from 350 to 800°C. The results reveal interesting properties. Indeed, the perovskite shows a huge dielectric constant which promotes its utilization in high-performance dielectric material applications. At a given temperature, ε' and tan(δ) decrease with increases in frequency. This trend was explained based on the Maxwell Wagner polarization model. The variations in dielectric loss (ε") with frequency obey the Giuntini theory based on the hopping model. As the temperature increases from 350 to 800°C, the binding energy increases from 0.22 to 0.34 eV, while the minimum hopping distance decreases from 2.16 to 0.12 pm. Consideration of the electric modulus analyzes showed that the relaxation mechanism is dominated at below 400°C by a shortrange movement of charge carriers, whereas at above that temperature, a long-range movement of charge carriers is dominant. This study presents a solid foundation for the polarization and dielectric properties of lanthanum ferrite, which is a lead-free, environmentally friendly material and a promising candidate for use in nonlinear optical applications and microwave devices.

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“…In recently, a signi cant amount of dedication was remunerated to the perovskite-type ABO 3 transition-metal oxides (TMOs) in photocatalytic eld due to its trivial band gap (2.0-2.5 eV) and high chemical stability. In order to enhance the physical properties of the LaFeO 3 compounds various ways have been used to synthesis such as co-precipitation technique [25], polymer pyrolysis method [5], hydrothermal method [26], polymerizable complex route [27], and microwave assisted method [28]. Identifying the suitable dopants and optimized synthesis procedure could make reaction method.…”

Section: Introductionmentioning

confidence: 99%

Conventional synthesis of perovskite structured LaTixFe1-xO3: A comprehensive evaluation on phase formation, opto-magnetic, and dielectrical properties

Raji

Kurapati

Ramachandran

et al. 2020

Preprint

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In the current study, we report a comprehensive evaluation of the microstructures, optical, dielectric and magnetic traits of Ti-substituted perovskite structured lanthanum ferrite with chemical compositions LaTixFe1−xO3 (x = 0, 0.05, 0.15, 0.25). X-ray diffraction with Rietveld refinement and Raman analysis confirmed that both pure and Ti-substituted LaFeO3 maintained single-phase orthorhombic phase with Pbnm symmetry. Fourier transform infrared spectroscopy (FTIR) studies revealed the information about the positions of the ions and their bonds within the lattice structure of the LaFeO3. The spherical shaped morphology of all products was confirmed by SEM. The quantitative chemical composition and their distribution were confirmed by EDAX and mapping. The UV-Vis spectroscopic studies showed an excitonic absorption edge at 590 nm is ascribed to the electronic transition from O2p→Fe3d. Optical band gap (Eg) values were assessed by applying Tauc schemes, showed that Eg values are in a narrow range (1.85–2.02 eV). The dielectric properties such as, dielectric constant (ε’), dielectric loss (tan δ) was examined by varying with temperature and frequency. The magnetic results revealed weak ferromagnetic nature trait at 300 K. The variation in Ms (saturation magnetization), Hc (coercivity) and Mr (remanence) values were observed with increasing Ti substitution level.

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Structural and electrical properties of calcium substituted lanthanum ferrite powders

Cited by 51 publications

References 24 publications

The influence of Ca substitution on LaFeO₃ nanoparticles in terms of structural and magnetic properties

The influence of Ca substitution on LaFeO₃ nanoparticles in terms of structural and magnetic properties

Dielectric properties of calcium-substituted lanthanum ferrite

Conventional synthesis of perovskite structured LaTixFe1-xO3: A comprehensive evaluation on phase formation, opto-magnetic, and dielectrical properties

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Structural and electrical properties of calcium substituted lanthanum ferrite powders

Cited by 51 publications

References 24 publications

The influence of Ca substitution on LaFeO3 nanoparticles in terms of structural and magnetic properties

The influence of Ca substitution on LaFeO3 nanoparticles in terms of structural and magnetic properties

Dielectric properties of calcium-substituted lanthanum ferrite

Conventional synthesis of perovskite structured LaTixFe1-xO3: A comprehensive evaluation on phase formation, opto-magnetic, and dielectrical properties

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The influence of Ca substitution on LaFeO₃ nanoparticles in terms of structural and magnetic properties

The influence of Ca substitution on LaFeO₃ nanoparticles in terms of structural and magnetic properties