1. Inorganic Functional Oxides and Nanomaterials
2. Microstructure and Physical Properties of Perovskite Epitaxial Film

1. Inorganic Functional Oxides and Nanomaterials (2009-Today)
Functional oxides have a wide variety of applications in the electronic industry. The discovery of new metal oxides with interesting and useful properties continues to drive much research in chemistry, physics, and materials science. In Functional Oxides five topical areas have been selected to illustrate the importance of metal oxides in modern materials chemistry: Noncentrosymmetric Inorganic Oxide Materials, Geometrically Frustrated Magnetic Materials, Lithium Ion Conduction in Oxides, Thermoelectric Oxides Transition Metal Oxides-Magnetoresistance and Half-Metallicity. The contents highlight structural chemistry, magnetic and electronic properties, ionic conduction and other emerging areas of importance, such as thermoelectricity and spintronics. After 3 years of effort, single-crystalline Cu
2O octahedral has been synthesized through electrochemical deposition. In addition we have studied the Microstructure and Physical Properties of
2O3 nanowires, CuO nanowire, Cu2O nanocubes and Cu2O octahedral.

Key Publications:
[1]. R. S. Cai, T. Li, Y. Q. Wang, C. Wang, L. Yuan, G. W. Zhou, Formation of modulated structures in single-crystalline hexagonal a-Fe
2O3 nanowires, Journal of Nanoparticle Research, 14(8), 1073 (2012).
[2]. Lu Yuan, Yiqian Wang, Rongsheng Cai, Qike Jiang, Jianbo Wang, Boquan Li, Guangwen Zhou, The origin of hematite nanowire growth during the thermal oxidation of iron, Materials Science and Engineering B, 177(3), 327-336 (2012).
[3]. Q. T. Du, J. S. Tan, Q. T. Wang, C. Y. Li, X. H. Liu, R. S. Cai, Y. H. Ding, Y. Q. Wang, Electrochemical deposition and formation mechanism of single-crystalline Cu
2O octahedra on aluminum, Journal of Analytical Methods in Chemistry, 2012, 406162/1-8 (2012).
[4]. Rediola Mema, Lu Yuan, Qingtian Du, Yiqian Wang, Guangwen Zhou, Effect of surface stresses on CuO nanowire growth in the thermal oxidation of copper, Chemical Physics Letters, 512(1-3), 87-91 (2011).
[5]. Lu Yuan, Yiqian Wang, Rediola Mema, Guangwen Zhou Driving force and growth mechanism for spontaneous oxide nanowire formation during the thermal oxidation of metals, Acta Materialia, 59(6), 2491-2500 (2011).
[6]. Y. Q. Wang, W. S. Liang, A. Satti, K. Nikitin, Fabrication and microstructure of Cu
2O nanocubes, Journal of Crystal Growth, 312(9), 1605-1609 (2010).

2. Microstructure and Physical Properties of Bi
0.4Ca0.6MnO3 and Ba0.5Sr0.5TiO3 Epitaxial Film (2010-Tody)
Perovskitemanganites of the formula R
1-xAxMnO3 (R being a trivalent rare earth and A being a divalent alkaline-earth ion) have attracted great attention recently due to their wide variety of electronic, magnetic, and structural states, and the coexisted and competitive mechanisms associated with the strong coupling among the spin, charge and orbital degrees of freedom. These materials are sensitive to magnetic, electric fields, pressure, and X-ray/visible light irradiation.The charge- and orbital-ordered (CO/OO) state in perovskite manganites has aroused a lot of interest for its colossal response to external stimuli.
Ferroelectric thin films including BaTiO
3, SrTiO3, and (Ba,Sr)TiO3(BSTO) have received great attention because of their potential applications for various functional devices. Extensive research work has indicated that the dielectric properties of epitaxial BSTO thin film strongly depend on internal stress and defect structure. For BSTO thin films grown on a single-crystalline substrate such as LaAlO3, there is a lattice mismatch (about 3.8%) and difference in their thermal coefficients. These differences lead to the formation of dislocations, stacking faults (SFs), and antiphase domains in the epitaxial film. These defects could increase the dielectric loss and reduce the tuneability of the film. Thus, it is necessary to carry out a comprehensive investigation of the defect structures in epitaxial BSTO films.

Key Publications:
[1]. Y. H. Ding, R. S. Cai, Y. Q. Wang, Y. Z. Chen, J. R. Sun, Dislocations in Bi
0.4Ca0.6MnO3 epitaxial film grown on (110) SrTiO3 substrate, Materials Letters, 67(1), 67-69 (2012).
[2]. Y. Q. Wang, W. S. Liang, W. J. Kong, P. K. Petrov, N. M. Alford, Structural engineering of Ba
0.5Sr0.5TiO3 epitaxial film, Thin Solid Films, 520(18), 5918-5921 (2012).
[3]. Li Chun-Yan£¬Liu Xue-Hua£¬Diao Fei-Yu, Liang Wen-Shuang, Wang Yi-Qian, Petrov Peter, Alford Neil, Microstructural defects and their formation mechanisms in Ba
0.75Sr0.25TiO3 epitaxial film, Journal of Inorganic Materials, 27(3), 285-290 (2012).
[4]. Y. H. Ding, Y. Q. Wang, R. S. Cai, Y. Z. Chen, J. R. Sun, Charge ordering modulations in Bi
0.4Ca0.6MnO3 film with a thickness of 110 nm, Chinese Physics B, 21(8), 087502 (2012).
[5]. Y. H. Ding, Y. Q. Wang, R. S. Cai, Y. Z. Chen, J. R. Sun, Effect of anisotropic strain on the charge ordering behavior in Bi
0.4Ca0.6MnO3 films, Applied Physics Letters, 99(19), 191914 (2011).
[6]. Y. Q. Wang, W. S. Liang, P. K. Petrov, N. M. Alford, Antiphase boundaries in Ba
0.75Sr0.25TiO3 epitaxial film grown on (001) LaAlO3 substrate, Applied Physics Letters, 98(9), 091910 (2011).
[7]. Y. H. Ding, R. S. Cai, Q. T. Du, Y. Q. Wang, Y. Z. Chen, J. R. Sun, Microstructure evolution of Bi
0.4Ca0.6MnO3 epitaxial films with different thickness, Journal of Crystal Growth, 317(1), 115-118 (2011).
[8]. Y. Q. Wang, W. S. Liang, P. K. Petrov, N. M. Alford, Dissociation of misfit and threading dislocations in Ba
0.75Sr0.25TiO3 epitaxial film, Materials Characterization, 62(3), 294-297 (2011).



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