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Deposition of YBCO Thin Film by Aerosol Assisted Spray Pyrolysis Using Nitrates
Byeong-Joo Kim,Seok-Kwan Hong,Jae-Geun Kim,Jung-Ho Kim,Dou, S X,Dunlop, L,Kursumovic, A,MacManus-Driscoll, J L,Hee-Gyoun Lee,Gye-Won Hong IEEE 2011 IEEE transactions on applied superconductivity Vol.21 No.3
<P>Coated conductor by MOCVD shows the best Ic × L performance currently, but cost reduction is still ongoing issue. R&D effort for a process capable of utilizing cheap alternative precursors were tried by many research groups but few of them showed results having potential for replacing current MOCVD. Spray pyrolysis method adopting ultrasonic atomization was tried as one of the possible options. Y123 films have been deposited on LaAlO<SUB>3</SUB> (100) single-crystal and IBAD substrates by aerosol assisted spray pyrolysis method. Ultrasonic atomization was used in order to generate fine droplets of precursor solution made of Y, Ba, Cu nitrate. A pre-heater was located between spraying nozzle and substrate for fast drying and enhancing decomposition of precursors. SEM and XRD observation revealed that deposited films have smooth and dense microstructure. The influence of operating parameters such as cation stoichiometry, oxygen partial pressure, substrate temperature on the microstructure, formation of superconducting 123 phases and superconducting properties of deposited films were tested. Ex-situ conversion was tried to decrease the possible reactions between precursor compounds and buffer layer materials of metal substrate showed the possibility of adopting this technique for epitaxial growth of 123 phase on metal substrate.</P>
Cho, Seungho,Yun, Chao,Kim, Yoon Seo,Wang, Han,Jian, Jie,Zhang, Wenrui,Huang, Jijie,Wang, Xuejing,Wang, Haiyan,MacManus-Driscoll, Judith L. Elsevier 2018 Nano energy Vol.45 No.-
<P><B>Abstract</B></P> <P>Lead-free perovskite oxide thin films prepared by alloying of titanates and materials with lower melting points are shown to have enhanced ferroelectric and dielectric properties. BaTiO<SUB>3</SUB> (or SrTiO<SUB>3</SUB>) with 25% addition of BiFeO<SUB>3</SUB> has much improved crystalline perfection because of the lower melting point of the BiFeO<SUB>3</SUB> giving enhanced growth kinetics. The maximum dielectric peak temperature of BaTiO<SUB>3</SUB> is increased by ~ 200°C and leakage currents are reduced by up to a factor of ~ 100. The loss tangent reduces up to 300°C, with a factor of > 14 reduction at room temperature. The dielectric breakdown strength is higher by a factor of ~ 3 (> 2200kVcm<SUP>−1</SUP>) and from room temperature up to 500°C the dielectric constant is > 1000. Also, a low variation of dielectric constant of ~ 9% from room temperature to 330°C is obtained, compared to ~ 110% for BaTiO<SUB>3</SUB>. The maximum polarization (<I>P</I> <SUB>max</SUB>) is double that of BaTiO<SUB>3</SUB>, at 125.3μCcm<SUP>−2</SUP>. The film has high energy storage densities of > 52Jcm<SUP>−3</SUP> at 2050kVcm<SUP>−1</SUP>, matching Pb-based ferroelectric films. The strongly improved performance is important for applications in energy storage and in high temperature (up to 300°C) capacitors as well as wider application in other electronic and energy technologies.</P> <P><B>Highlights</B></P> <P> <UL> <LI> High crystallinity is achieved by mixing titanate with a lower melting point material. </LI> <LI> The film with enhanced crystallinity has strongly enhanced dielectric properties. </LI> <LI> The film has high energy storage densities of > 52Jcm<SUP>−3</SUP>, matching Pb-based films. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Microscopic role of carbon on MgB2 wire for critical current density comparable to NbTi
Kim, Jung Ho,Oh, Sangjun,Heo, Yoon-Uk,Hata, Satoshi,Kumakura, Hiroaki,Matsumoto, Akiyoshi,Mitsuhara, Masatoshi,Choi, Seyong,Shimada, Yusuke,Maeda, Minoru,MacManus-Driscoll, Judith L,Dou, Shi Xue Nature Publishing Group 2012 NPG Asia Materials Vol.4 No.-
Origin of Improved Photoelectrochemical Water Splitting in Mixed Perovskite Oxides
Li, Weiwei,Jiang, Kai,Li, Zhongguo,Gong, Shijing,Hoye, Robert L. Z.,Hu, Zhigao,Song, Yinglin,Tian, Chuanmu,Kim, Jongkyoung,Zhang, Kelvin H. L.,Cho, Seungho,MacManus-Driscoll, Judith L. Wiley (John WileySons) 2018 ADVANCED ENERGY MATERIALS Vol.8 No.31
Lloyd-Hughes, J.,Mosley, C. D. W.,Jones, S. P. P.,Lees, M. R.,Chen, A.,Jia, Q. X.,Choi, E.-M.,MacManus-Driscoll, J. L. American Chemical Society 2017 Nano letters Vol.17 No.4
<P>Colossal magnetoresistance (CMR) is demonstrated at terahertz (THz) frequencies by using terahertz time-domain magnetospectroscopy to examine vertically aligned nanocomposites (VANs) and planar thin films of La<SUB>0.7</SUB>Sr<SUB>0.3</SUB>MnO<SUB>3</SUB>. At the Curie temperature (room temperature), the THz conductivity of the VAN was dramatically enhanced by over 2 orders of magnitude under the application of a magnetic field with a non-Drude THz conductivity that increased with frequency. The direct current (dc) CMR of the VAN is controlled by extrinsic magnetotransport mechanisms such as spin-polarized tunneling between nanograins. In contrast, we find that THz CMR is dominated by intrinsic, intragrain transport: the mean free path was smaller than the nanocolumn size, and the planar thin-film exhibited similar THz CMR to the VAN. Surprisingly, the observed colossal THz magnetoresistance suggests that the magnetoresistance can be large for alternating current motion on nanometer length scales, even when the magnetoresistance is negligible on the macroscopic length scales probed by dc transport. This suggests that colossal magnetoresistance at THz frequencies may find use in nanoelectronics and in THz optical components controlled by magnetic fields. The VAN can be scaled in thickness while retaining a high structural quality and offers a larger THz CMR at room temperature than the planar film.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2017/nalefd.2017.17.issue-4/acs.nanolett.7b00231/production/images/medium/nl-2017-00231y_0005.gif'></P>
Kang, Bo Soo,Stan, Liliana,Usov, Igor O.,Lee, Jung‐,Kun,Harriman, Tres A.,Lucca, Don A.,DePaula, Raymond F.,Arendt, Paul N.,Nastasi, Michael,MacManus‐,Driscoll, Judith L.,Park, Bae Ho,Jia, WILEY‐VCH Verlag 2011 Advanced Engineering Materials Vol.13 No.12
<P><B>Abstract</B></P><P>A novel strain mismatch induced tilted epitaxy method has been demonstrated for producing high quality (000l) hexagonal films on (001) cubic substrates. Highly oriented hexagonal (000l) ZnO films are grown on cubic (001) MgO substrates using Sm<SUB>0.28</SUB>Zr<SUB>0.72</SUB>O<SUB>2−<B>δ</B></SUB> (SZO) as a template. The large lattice mismatch of >13% between the obvious crystallographic matching directions of the template and substrate means that cube‐on‐cube epitaxy is energetically unfavorable, leading to growth instead of two high index, low energy compact planes, close to the {111} orientation. These planes give three different in‐plane orientations resulting from coincidence site lattice matching (12 in‐plane orientations in total) and provide a pseudo‐hexagonal symmetry surface for the ZnO to grow on. The texture of the ensuing (000l) ZnO layer is markedly improved over the template. The work opens up both a new avenue for growing technologically important hexagonal structures on a range of readily available, (001) cubic substrates, as well as showing that there are wide possibilities for heteroepitaxial growth of a range of dissimilar materials.</P>