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    Item type:Publication,
    EFFECT OF FIRING TEMPERATURES ON THE PHASE STRUCTURE AND ELECTRICAL PROPERTIES OF BNT-BT-0.1NT CERAMICS SYNTHESIZED VIA THE SOLID-STATE COMBUSTION TECHNIQUE
    (2025-01-01)
    Thatawong, Bhoowadol
    ;
    Tagerd, Kanyanut
    ;
    Vittayakorn, Naratip
    ;
    Udeye, Thanya
    ;
    Bongkarn, Theerachai
    Lead-free ceramic materials of 0.9(0.92Bi0.5Na0.5TiO3-0.08BaTiO3)-0.1NaTaO3 or BNT-BT-0.1NT were obtained using glycine as fuel by a solid-state combustion process. The significance of heat treatment conditions, including calcination at 600-800°C for 2 h and sintering at 1075-1175°C for 2 h, on the structure of the phase, microstructure, electrical and energy-storage properties of BNT-BT-0.1NT ceramics were performed. The perovskite phase was presented for all powder samples. BNT-BT-0.1NT powders calcined at the temperature of 750°C for 2 h showed a 100% pure perovskite phase. The particles morphology exhibited spherical shapes with a wide distribution. As the calcination temperature increased, the average particle size grew from 340 nm to 370 nm. Rietveld refinement confirmed that the BNT-BT-0.1NT ceramics possessed a uniform ABO3 structure with cohabiting of rhombohedral (R), tetragonal (T), and cubic (C) phases. With a rise in sintering temperature, the average grain size expanded from 0.85 μm to 2.66 μm, while the remnant polarization (P<inf>r</inf>) and coercive field (E<inf>c</inf>) decreased. The samples sintered at 1150oC for 2 h, the ceramic highlighted the highest dielectric constant (ε<inf>max</inf> ~ 1827), high density of 5.83 g/cm<sup>3</sup>. Under an applied electric field of 70 kV/cm, the maximum energy storage density reached 0.71 J/cm<sup>3</sup>.
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    Item type:Publication,
    ELECTRICAL AND MAGNETIC PROPERTIES OF MULTIFERROIC Co0.6Zn0.4Fe1.7Mn0.3O4 DOPED 0.99Bi0.47Na0.47Ba0.06TiO3-0.01Ba(Sn0.70Nb0.24)O3 CERAMICS SYNTHESIZED VIA THE SOLID-STATE COMBUSTION TECHNIQUE
    (2025-01-01)
    Luangpangai, Anupong
    ;
    Chuai, Phomphon
    ;
    Rittidech, Aurawan
    ;
    Pinitsoontorn, Supree
    ;
    Jantaratana, Pongsakorn
    Multiferroic (1-x)[0.99Bi<inf>0.47</inf>Na<inf>0.47</inf>Ba<inf>0.06</inf>TiO<inf>3</inf>-<inf>0.01</inf>Ba(Sn<inf>0.70</inf>Nb<inf>0.24</inf>)O<inf>3</inf>]-xCo<inf>0.6Z</inf>n<inf>0.4</inf>Fe<inf>1.7</inf>Mn<inf>0.3</inf>O<inf>4</inf> (abbreviated as BNBT-BSN-xCZFMO) ceramics with x ranging from 0 to 0.20 were fabricated using the solid-state combustion technique. The effect of varying BNBT-BSN: CZFMO ratios on the phase structure, microstructure, electrical and magnetic properties was investigated. X-ray diffraction (XRD) analysis of pure BNBT-BSN showed a perovskite structure with rhombohedral and tetragonal phases. The doped BNBT-BSN-xCZFMO ceramics displayed coexisting rhombohedral, tetragonal, and cubic spinel phases, with the cubic spinel phase increasing when the CZFMO content increased. In addition, the XRD peaks shifted to higher angles as the CZFMO content increased, indicating a decrease in lattice parameters. The dielectric constant decreased with higher CZFMO content and higher frequencies. The pure BNBT-BSN ceramic exhibited a saturated P-E loop with a Pmax of 33.2 µC/cm<sup>2</sup>, Pr of 26.1 µC/cm<sup>2</sup>, and an Ec of 14.5 kV/cm. With increased CZFMO content, non-saturated and bloated P-E loops with lower Pmax, Pr, and Ec were observed, implying a rise in the leakage current. The addition of CZFMO induced ferromagnetic behavior in the ceramics, leading to an increase in Ms and a reduction in Hc as CZFMO content increased. The magnetoelectric coupling coefficient of BNBT-BSN-xCZFMO ceramics continuously increased with higher CZFMO content.
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    Item type:Publication,
    ELECTRIC AND MAGNETIC PROPERTIES OF Ni0.475Zn0.475Li0.025Al0.025Fe2O4 DOPED (Bi0.5Na0.5)0.94Ba0.06TiO3 CERAMICS PREPARED BY THE SOLID-STATE COMBUSTION METHOD
    (2025-01-01)
    Pattanakasem, Wiwat
    ;
    Sookboon, Chirarat
    ;
    Somsri, Widchaya
    ;
    Vittayakorn, Naratip
    ;
    Pinitsoontorn, Supree
    In this study, we synthesized (1-x)((Bi<inf>0.5</inf>Na<inf>0.5</inf>)<inf>0.94</inf>Ba<inf>0.06</inf>TiO<inf>3</inf>)-x Ni<inf>0.475</inf>Zn<inf>0.475</inf>Li<inf>0.025</inf>Al<inf>0.025</inf>Fe<inf>2</inf>O<inf>4</inf> [(1-x)BNBT-xNZLAF] ceramics with x= 0, 0.05, 0.10, 0.15, and 0.20 using the solid-state combustion method. The phase formation, microstructure, and dielectric, ferroelectric, ferromagnetic, and magnetoelectric properties were investigated. BNBT and NZLAF powders were calcined at 750°C and 900°C for 2 h., respectively. The calcined powders were then mixed in various ratios to produce (1-x)BNBT-xNZLAF composites, which were sintered at 1125°C for 2 h. X-ray diffraction analysis indicated that undoped BNBT ceramics exhibited a typical perovskite structure with coexisting rhombohedral (R) and tetragonal (T) phases. With increasing NZLAF content, the cubic spinel (C) phase emerged with the R and T perovskite phases. Rietveld refinement indicated a higher percentage of the C phase as x increased. When x increased from 0 to 0.10, the average grain size and density increased (from 1.0 to 9.8 m and 5.45 to 5.61 g/cm3, respectively) followed by a drop at higher NZLAF levels. Doping BNBT ceramics with NZLAF resulted in a reduction in the dielectric constant (εr), dielectric loss (tan δ), and remnant polarization (Pr). The undoped BNBT ceramic showed a saturated P-E hysteresis loop, while NZLAF doped ceramics exhibited unsaturated P-E loops and increased leakage current. Magnetic measurements showed a transition from diamagnetic to ferromagnetic behavior with NZLAF doping. As x increased, the remnant magnetization (Mr), saturation magnetization (Ms), and magnetoelectric coefficient also increased (Mr0.058 emu/g, Ms3.594 emu/g, and MEcoefficient 2.64 mV/cm•Oe at x=0.25). These results suggest that NZLAF-doped BNBT ceramics hold potential for multiferroic material applications.