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In this paper, La 1 − x CaxFeO3 (x = 0 , 0.1, 0.2, 0.3, 0.4, 0.5) perovskite samples were synthesized by sol–gel method. X-ray diffraction (XRD), transmission electron microscopy (TEM) and Mössbauer were used for measuring. XRD measurement shows that the unit cell volume of LaFeO3 gradually decreases with increasing Ca content. The morphology of the sample was observed by TEM, and there were significant changes in volume and size of the samples with different calcium contents. Mössbauer spectrum study found that with the gradual increase of Ca content, Fe 3. 5 + and Fe 4 + were formed in the sample. The study in this paper will provide a reference for future research on the effect of different calcium contents on the electronic structure of lanthanide ferrite. [ABSTRACT FROM AUTHOR]

The synthesis of REFe0.5Cr0.5O3 (RE = La, Y) using the sol–gel method is focused and their structural differences are investigated. The results of X‐ray diffraction show that the change of ion radius at position A leads to varying degrees of octahedral distortion and spatial group structure. The scanning electron microscopy analysis reveals micron‐level particles with clear boundaries, while energy‐dispersive X‐ray spectroscopy and room temperature Mössbauer spectra indicate the presence of Fe/Cr clusters in the sample and the transitional valence of iron. Disorder in the B position leads to a saturation moment that is lower than the theoretical value. The thermomagnetic profile shows a reversal of magnetization due to the interaction between the single‐ion magnetic anisotropy and the antisymmetric Dzyaloshinskii–Moriya (DM) interaction, with a broader peak is observed due to cluster formation. The difference in negative magnetic field is due to the difference in net magnetic moment caused by different DM intensities. [ABSTRACT FROM AUTHOR]

Herein, the effects of different Sr content doping on the crystal structure and electronic structure of La1−xSrxFeO3−δ (LSFO‐x, x = 0, 0.2, 0.5, 0.8, 1.0) are studied by X‐ray diffraction (XRD) and Mössbauer spectroscopy. It is shown in the XRD results that the structure of LSFO‐x changes from orthorhombic (Pnma [#62]) to cubic (Pm‐3m (#221)) to tetragonal (I4/mmm (#139)) with increasing strontium doping. It is shown in Mössbauer spectrum analysis that with the gradual increase of Sr doping, iron ions finally change from +3 oxidation state to +4 oxidation state after passing through an intermediate oxidation state of +3.5. The Fe3.5+ state can result from rapid electron exchange (Fe3+ + Fe4+ ⇋ Fe4+ + Fe3+) between iron ions of different oxidation states within the crystal structure; the study provides some reference for future research to study the effect of iron‐oxidation state on the specific activity of strontium‐doped LaFeO3. [ABSTRACT FROM AUTHOR]

In this paper, LaFe0.75Cr0.25O3 was synthesized by a citric acid combusting sol–gel method. The basic structural information is reflected by XRD. According to Mössbauer spectroscopy, the inhomogeneous distribution of Cr contributes to magnetic dilution, thus appearing the coexistence of singlet and sextet. Simultaneously, the rare superparamagnetic relaxation appears due to "critical superparamagnetism" caused by small magnetic clusters with intervening sizes. Oxygen vacancies of synthesized sample are also found. The DC magnetization curve reveals the magnetization reversal phenomenon, which is related to the competition between the Dzyaloshinsky–Moriya interaction (DMI) and the magnetic anisotropy belonging to single ions. At 300 K, LCFO reveals weak magnetism. No magnetic transition is observed below 400 K. [ABSTRACT FROM AUTHOR]

Herein, the multiferroic perovskite Er0.9La0.1Cr0.8Fe0.2O3 was synthesized using the sol–gel method, and its structure and multiferroic properties were investigated. The magnetic order of Er0.9La0.1Cr0.8Fe0.2O3 was analyzed through magnetic entropy change curves. Furthermore, a four‐sublattice molecular field model was constructed to study the spin reorientation phenomena and explain the differences between various spin redirections through magnetic order correction. This work will provide a new perspective for studying the properties of type II multiferroic materials. [ABSTRACT FROM AUTHOR]

In this paper, La 2/3 Ca 1/3 Fe 1-x Mn x O 3-δ (x = 0–0.6) nano particles have been prepared by the sol-gel method. X-ray diffraction (XRD) analysis revealed that with the increase of Mn doping content, the main diffraction peak shifted to the right, the lattice parameters decreased overall, and the degree of lattice distortion gradually reduced. X-ray photoelectron spectroscopy (XPS) analysis indicates that the valence states of Fe and Mn in the system coexist as trivalent and tetravalent, and with the increase in Mn doping, the ratio of Fe3+/Fe4+ decreases, while the ratio of Mn3+/Mn4+ slightly increases. The results of Mössbauer spectrum analysis revealed that as the Mn doping content increased, some Fe ion valence states in the system gradually changed from Fe3+ to Fe4+, and the presence of the paramagnetic phase became increasingly prominent. Furthermore, with the increase of Mn doping content, the degree of lattice distortion in the system decreased, which is consistent with the results obtained from the XRD analysis. This work will provide a reference for future research on the effects of manganese doping in similar systems. Fig. 1: Mössbauer spectra of LCFMO-x at 298 K. The red fitting line denotes the total fitting result, the blue and green fitting lines respectively represent Sextet 1 and Sextet 2, and the purple fitting line signifies Doublet 1.The impact of varying amounts of Mn doping on the charge state of Fe ions and their local environment within LCFMO-x (x = 0–0.6) was investigated using 57Fe Mössbauer spectroscopy. The Mössbauer spectra of the LCFMO-x samples, measured at room temperature, are depicted in Fig. 1. [Display omitted] • Investigation of Mn Doping: The study provides a comprehensive investigation into the effects of Mn doping on LaCaFeO 3 (LCFMO), a material with significant potential in various applications. • 57Fe Mössbauer Spectroscopy Analysis: In addition to XRD and XPS, the study also utilized 57Fe Mössbauer spectroscopy to examine the impact of Mn doping on the charge state of Fe ions and their local environment within LCFMO-x (x = 0–0.6). • Changes in Charge State and Local Environment: The results from the Mössbauer spectra suggest that as the amount of Mn doping increases, the charge state of Fe ions and their local environment within LCFMO-x undergo changes. This indicates the complex interplay of factors in the system and provides valuable insights into the effects of Mn doping on LCFMO. [ABSTRACT FROM AUTHOR]

The wide application of LaMn 0.5 Fe 0.5 O 3 perovskite is due to its very complex magnetic and structural properties. Orthorhombic perovskite structure samples were prepared by sol-gel method. The system has a special spin glass state (Néel temperature below freezing temperature). Therefore, there is a transition for the main magnetic phase from strong antiferromagnetism to ferrimagnetism and finally to superparamagnetism as the temperature increases. The typical ferromagnetic and antiferromagnetic competing exchange bias phenomenon appears in the M − H curve at 5 K. We have simulated the thermal and magnetic characteristics of the system through the XYZ model and particle swarm optimization and obtained accurate anisotropy parameters. The transitions of the Mössbauer spectra at different temperatures reflect the changes in the macroscopic magnetic properties of the system. Finally, we can explain the relaxation peak behavior of Mössbauer spectra well by the relationship between the relaxation hyperfine field and temperature. This study will provide a good illustration and reference for the magnetic nature of strongly magnetic disordered LaMn 0.5 Fe 0.5 O 3 systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Single-phase samples were prepared by the sol–gel combustion method. • The macroscopic magnetism at room temperature was judged by the magnetization curve and Mössbauer spectrum. • A good thermomagnetic curve was fitted by molecular field theory, and the exact exchange constant was obtained. • The special thermally induced spin behavior of A-site Pr3+ ions are described. Ultrafast spin control plays a pivotal role in condensed matter physics. In this study, we analyzed the macroscopic magnetization of the PrFe 0.1 Cr 0.9 O 3 system by molecular field model fitting. And the whole process of system spin reorientation is accurately calculated in the fitting process. It is found that, unlike the rare-earth perovskites we have previously studied, PrFe 0.1 Cr 0.9 O 3 exhibits spin-reversion properties during the reorientation process. This research will lay a theoretical foundation for precise spin control in the future. [ABSTRACT FROM AUTHOR]