Synthesis, growth and characterization of L-Leucine Magnesium Nitrate Hexahydrate crystal

L-Leucine Magnesium Nitrate HexaHydrate ([Formula: see text]) crystal is a nonlinear optical (NLO) material of semiorganic type. It has grown using a slow evaporation solution growth (SEST) technique at elevated temperature (40∘C) by dissolving LL+MNHH in double distilled water. It was crystalized and recrystalized from a supersaturated solution by stirring it for several hours to get high optical perfection. The X-ray diffraction studies confirmed the presence of the intermixed compound in the [Formula: see text] crystal and possess monoclinic structure. Fourier transform infrared spectroscopy (FTIR) spectrum identified the functional groups of the grown crystal. The crystal has very good optical absorption and transparency in the UV–Vis region. The thermal analysis revealed the thermal stability of the crystal. The dielectric study shows that dielectric constant and dielectric loss decrease at higher frequencies. The crystal showed nonlinear property by second-harmonic generation (SHG) study. This type of material with fair nonlinearity is useful in optoelectronics application devices.

History of Korea Ferroelectric Research

Research Center for Dielectric Study was supported by the Korean Research Foundation from the government. In 1991, Professor Jang, Min-Soo along with 22 other professors, received a research grant of 7 billion won for 10 years, which enabled the Korean Ferroelectric Research Society to be competitive globally. The 9th International Meeting on Ferroelectricity, which is held every four years, was held in Seoul in 1997. The first dielectric joint symposium organized by condensed-matter physics and materials science researchers was held in 2005. The Korean Dielectrics Society was established at Muju resort in 2017, with Professors Tae Won Noh and Jaichan Lee representing the condensed-matter physics and materials science communities, respectively. Currently, more than 300 members are actively participating in the Korean Dielectric Society. To celebrate the 100th anniversary of ferroelectricity, which was fist discovered in Rochelle salt by Joseph Valasek in 1921, we organized a special session in the 2020 Korean Physics Society Fall Meeting.

Investigation of the Phase Transitions and Magneto-Electric Response in the 0.9(PbFe0.5Nb0.5)O3-0.1Co0.6Zn0.4Fe1.7Mn0.3O4 Particulate Composite

Multiferroic composites with enhanced magneto-electric coefficient are suitable candidates for various multifunctional devices. Here, we chose a particulate composite, which is the combination of multiferroic (PbFe0.5Nb0.5O3, PFN) as matrix and magnetostrictive (Co0.6Zn0.4Fe1.7Mn0.3O4, CZFMO) material as the dispersive phase. The X-ray diffraction analysis confirmed the formation of the composite having both perovskite PFN and magnetostrictive CZFMO phases. The scanning electron micrograph (SEM) showed dispersion of the CZFMO phase in the matrix of the PFN phase. The temperature-dependent magnetization curves suggested the transition arising due to PFN and CZFMO phase. The temperature-dependent dielectric study revealed a second-order ferroelectric to the paraelectric phase transition of the PFN phase in the composite with a small change in the transition temperature as compared to pure PFN. The magnetocapacitance (MC%) and magnetoimpedance (MI%) values (obtained from the magneto-dielectric study at room temperature (RT)) at 10 kHz were found to be 0.18% and 0.17% respectively. The intrinsic magneto-electric coupling value for this composite was calculated to be 0.14 mVcm−1Oe−1, which is comparable to other typical multiferroic composites in bulk form. The composite PFN-CZFMO exhibited a converse magneto-electric effect with a change in remanent magnetization value of −58.34% after electrical poling of the material. The obtained outcomes from the present study may be utilized in the understanding and development of new technologies of this composite for spintronics applications.

Structural, optical and electrical properties of Mn-doped ZnFe2O4 synthesized using sol-gel method

Samples with doping of Mn (0, 2, and 4%) in ZnFe2O4 were prepared by sol-gel chemical route at 80oC. X-ray powder diffraction and Raman spectrum analysis were used to determine the preliminary phase of obtained samples. W-H and SSP plots were used to determine the crystallite size and micro-strain of samples. Using zeta potential and scanning electron microscope, the surface charge and morphology of the prepared samples were studied. The optical bandgap of sample suggested that it was semiconducting. The dielectric characteristics of samples were examined as a function of temperature at various frequencies (1 KHz, 10 KHz, 100 KHz, and 1 MHz) (60-600oC). Dielectric study revealed the presence of interfacial and orientational polarization, with dielectric constants and dissipation factors ranging from (0.7–460) to (0.3–0.8), remain thermally stability up to 300oC. In samples ZF-0, ZF-2, and ZF-4, the thermal dependence of DC conductivity demonstrates Arrhenius transport with one, two, and three regions of conduction, respectively. The sources of charge carrier in samples were Vo,e1 defects (Vo - 2FE2+ Fe3+') and (2M3+ Zn2+ - 2FE2+ Fe3+'). The current work could help identify possible applications in semiconductor devices, thermally stable capacitors, and as mixed ionic electronic conductors in solid oxide fuel cells.