Oxide lithium-manganese ferrite spinel representation, with stoichiometry LiMn_0.5Fe₂O₄, in the (110) plane.

Due to remarkable dielectric features, such as a large dielectric constant, strong electrical conductivity, high capacitance, and low dielectric loss, hybrid materials have lately seen a huge number of applications in the field of optoelectronics. These are critical characteristics that qualify the performance of optoelectronic devices, particularly field-effect transistor components (FETs). Here, the hybrid compound 2-amino-5-picoline tetrachloroferrate(III) (2A5PFeCl₄) was synthesised by using the slow evaporation solution growth method at room temperature. Structural, optical, and dielectric properties have been investigated. The 2A5PFeCl₄ compound crystallises in the monoclinic system (P2₁/c space group). Its structure can be described as a successive layering of inorganic and organic parts. [FeCl₄]⁻ tetrahedral anions and 2-amino-5-picolinium cations are connected by N–H⋯Cl and C–H⋯Cl hydrogen bonds. The optical absorption measurement confirms the semiconductor nature with a band gap of around 2.47 eV. Additionally, the structural and electronic properties of the title compound have been investigated theoretically through DFT calculations. At low frequencies, this material has significant dielectric constants (ε ∼10⁶). Furthermore, the high electrical conductivity, low dielectric loss at high frequencies, and high capacitance show that this new material has great dielectric potential in FET technologies. Due to their high permittivity, these compounds can be employed as gate dielectrics.

There has been a lot of interest in the development of a novel hybrid material based on mercury that has fascinating structural properties. In this paper, single crystals of [C₈H₁₀NO]₂HgBr₄ was successfully synthesized by the slow evaporation method at room temperature. In fact, the latter crystallizes in the orthorhombic system (Cmca space group) with cell parameters a = 20.824(2) Å, b = 15.352(1) Å and c = 13.700(1) Å and Z = 8. Its structure is constituted by one [C₈H₁₀NO]⁺ cation and one type of isolated anion [HgBr₄]²⁻ tetrabromomercurate(II). The atomic arrangement presents an alternation of organic and inorganic layers along the a-axis. To maintain the cohesiveness of the structure, these components are joined via π⋯π interactions and hydrogen bonds (N–H⋯Br and N–H⋯O). A general network of hydrogen bonds ensures the interconnection of several entities. Greater knowledge of these interactions has been obtained based on the Hirshfeld surface analysis and 2D fingerprint plots. The analysis of complex impedance spectra shows that the electrical properties of the material are heavily dependent on frequency and temperature. The obtained results were analyzed by fitting the experimental data to an equivalent circuit model. The temperature dependence of conductivity and the relaxation frequency ω_max fulfill the Arrhenius relation and activation energies are estimated. The material follows Jonscher's universal dynamic law or here there is a decrease in the exponent ‘s’ as the temperature increases. This result indicates that the Correlated Barrier Hopping (CBH) model represents the conduction mechanism. Besides, the non-Debye type conductivity relaxation is revealed by the electrical modulus analysis.

Ferrite compounds have recently attracted significant interest because of their multifunctional properties. This work investigates the optical, magnetic, and dielectric properties of a LiMn_0.5Fe₂O₄ ferrite prepared by a solid-state reaction. Raman spectroscopy analysis substantiated the presence of the 5 active modes representing the vibration of the oxygen anion at both tetrahedral and octahedral sites. The direct optical band gap was estimated to be 3.51 eV, which indicates the semiconductor behavior of the compound. A theoretical modulation of the hysteresis loop was done to confirm the dominance of the ferromagnetic contribution over the antiferromagnetic one. Furthermore, the dielectric permittivity result indicated a colossal value of the order of 10³. The dielectric losses are characterized by the Giuntini law to extract the relaxation process, which is hidden by the DC-conductivity process. Our results indicate the potential of LiMn_0.5Fe₂O₄ for applications in multifunctional devices.

The present study deals with two compounds, ( x = 0.05 and x = 0.1), synthesized using a sol-gel auto-combustion method.