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Author: search.filters.author.Kahatta, Sagulthai

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    Synthesis and characterization of thermochromic la 0.75 Ca 0.25MnO3 perovskite manganites nano-powders by microwave-assisted solution combustion synthesis
    (2014-01-02)
    Kahatta, Sagulthai
    ;
    Techitdheera, Wicharn
    ;
    Chaiyo, Nopsiri
    ;
    Pecharapa, Wisanu
    ;
    Vittayakorn, Naratip
    The microwave-assisted solution combustion synthesis was developed for application with initially synthesized thermochromic perovskite manganese oxide La0.75Ca0.25MnO<inf>3</inf> nano-powders. Dry and very fine powders were obtained after one-step combustion reaction for less than 10 min in a modified domestic microwave oven. The thermal behavior, phase formation and purity of the precursor, and as-synthesized and calcined powders, were investigated by TGA/DTA, X-ray diffraction (XRD) and FT-IR techniques. The morphology of the powder obtained was characterized using a scanning electron microscope (SEM). The XRD pattern and FT-IR results showed that as-synthesized La <inf>0.75</inf>Ca<inf>0.25</inf>MnO<inf>3</inf> powders were crystalline, and the monophasic perovskite phase occurred with an average crystallite size of 30.46 ± 5.54 nm for 6 h at a relatively low calcination temperature of 900°C. The small particle size obtained by SEM suggested a high specific surface area and high sinterability. This method was found to be simple, rapid and cheap, and an effective way to prepare nano-size perovskite powders. © 2014 Taylor and Francis Group, LLC.
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    Microwave-assisted solution combustion synthesis and characterization of thermoelectric Ca3Co2O6 powders
    (2013-10-29)
    Kahatta, Sagulthai
    ;
    Chaiyo, Nopsiri
    ;
    Ruttanapun, Chesta
    ;
    Techitdheera, Wicharn
    ;
    Pecharapa, Wisanu
    The microwave-assisted solution combustion synthesis was applied to the initial synthesizing of Ca<inf>3</inf>Co<inf>2</inf>O<inf>6</inf> powder using glycine as a fuel and nitrate as an oxidant. The assynthesized powders were calcined at 700-1,000°C for 4h. Product characterization was performed using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and Scanning electron microscope (SEM). The fuel-to-oxidizer molar ratio was found to affect the combustion reaction and character of the powder obtained. The phase composition of powder after calcination at various temperatures has shown that the formation of Ca<inf>3</inf>Co<inf>2</inf>O<inf>6</inf> occurs directly. The calcined powder possesses a rhombohedral crystal structure with an X-ray diffraction pattern that could be matched with the Ca<inf>3</inf>Co<inf>2</inf>O<inf>6</inf>JCPDS: 89-0629. This method is a simple way of synthesizing fine Ca<inf>3</inf>Co<inf>2</inf>O<inf>6</inf> powder with a low calcination temperature. © (2013) Trans Tech Publications, Switzerland.
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    Optical and electronic transport properties of p-type CuCoO2 transparent conductive oxide
    (2013-09-18)
    Ruttanapun, Chesta
    ;
    Sa-Nguan-Cheep, Minraya
    ;
    Kahatta, Sagulthai
    ;
    Buranasiri, Prathan
    ;
    Jindajitawat, Phumin
    The CuCoO2 sample has been synthesized by a conventional solid-state reaction method to investigate electronic transport and optical properties for p-type transparent conducting oxide materials. The crystal structure was characterized by XRD. The Seebeck coefficient and electrical conductivity were measured in the high temperature. The UV-VIS-NIR and FTIR spectra were analyzed at room temperature. The XRD peaks confirm the samples forming the delafossite structure phase. The Seebeck coefficient sign confirms the samples displays the p-type conducting. The electronic transport energy for activating free carrier production and conduction contain 0.276 eV and 0.131 eV, respectively. The optical direct gap is 3.65 eV which is a visible-transparent oxide material. These results support that the CuCoO2 oxide compound is p-type transparent conducting oxide materials. © 2013 SPIE.
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    Optical properties of Cu0.95Pt0.05Fe0.97Sn0.03O2 for p-type transparent conducting oxide materials
    (2013-08-30)
    Ruttanapun, Chesta
    ;
    Kahatta, Sagulthai
    ;
    Boonchom, Banjong
    ;
    Vittayakorn, Naratip
    ;
    Thongkam, Montree
    The Cu<inf>0.95</inf>Pt<inf>0.05</inf>Fe<inf>0.97</inf>Sn<inf>0.03</inf>O<inf>2</inf> sample has been synthesized by a solid-state reaction to investigate optical properties of materials of transparent conducting oxide. Crystal structure was characterized by XRD. The Seebeck coefficient and electrical conductivity were measured in the high temperature (300 to 860 K), while the XPS and UV-VIS-NIR spectra were analyzed at room temperature. The XRD peaks confirm the samples forming the delafossite structure phase. The Seebeck coefficient reveals the samples displays the p-type conducting. The XPS spectra show the Sn2+ state stabling in this compound. The optical direct gap is 3.45 eV as a visible-transparent material. These results support that the Cu<inf>0.95</inf>Pt<inf>0.05</inf>Fe<inf>0.97</inf>Sn<inf>0.03</inf>O<inf>2</inf> oxide compounds, of which the Cu<sup>1+</sup> and Fe<sup>3+</sup> sites are substituted by the Pt<sup>1+</sup> and Sn<sup>2+</sup> ions respectively, are p-type transparent conducting oxide materials. © (2013) Trans Tech Publications, Switzerland.