We have participated in study of electromagnetic properties of topic bulk high-Tc superconductors of the (Nd,Eu,Gd)BaCuO composition in which a tiny doping by Nb, Mo or Ti oxides leads to a substantial critical current density enhancement. In the composite doped by Nb2O5 the critical current density, Jc, reached the record values of 925 kA/cm2 (65 K), both in the remnant state and at 4.5 T, and 100 kA/cm2 at the self-field at 90 K [1]. While the former value came close to the level observed in thin films, the latter value, observed only a few degrees under Tc, is as high as standard values observed in YBaCuO at 77.3 K (boiling point of liquid nitrogen). Taking into account the nearly exponential decay of Jc with temperature, the present material shifts the standards several times and enables levitation with liquid oxygen (90.2 K) or argon (87 K).
In cooperation with the colleagues from Jiao Tong University in Shanghai we took part in the research focused on growth mechanisms of thin layers of REBaCuO (RE=Y,Sm) with various growth orientations. Besides the importance of the understanding of the controlled growth of thin layers with variable orientation itself, the boundaries between differently oriented grains have a great potential in future microelectronics as effective Josephson junctions [2-4].
[1] M. Muralidhar, M. Jirsa et al., Record flux pinning in melt-textured NEG-123 doped by Mo and Nb nanopar-ticles Appl. Phys. Letters 92, 162512 (2008), doi:10.1063/1.2908929
[2] Y. Q. Cai et al., Preferential Growth and Peculiar Interfacial Atomic Configuration of the YBCO Liquid-Phase Epitaxial Film with 45o In-Plane Alignment, Cryst. Growth Des. 7 (2009) 3218-3221, doi:10.1021/cg801269z
[3] L. J. Sun et al., Real-Time Observation of Growth and Orientation of Sm-Ba-Cu-O Phases
on a Sm-211 Whisker Substrate by High-Temperature Optical Microscopy, Cryst. Growth Des. 9 (2009) 898-902, doi:10.1021/cg8006525
[4] Ch. Y. Tang et al., Crystallographic Axis Transition of Sm1+xBa2-xCu3O7-δ Film Prepared by Liquid Phase Epitaxy (LPE), Cryst. Growth Des. 9 (2009) 1339-1343, doi:10.1021/cg800443q
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