caa a22 4500 445382635 CHVBK 20180317143022.0 cr unu---uuuuu 170323e20111101xx s 000 0 eng 10.1007/s10948-011-1187-4 doi (NATIONALLICENCE)springer-10.1007/s10948-011-1187-4 Normal-state Conduction Mechanisms in GdBa2Cu3− x Ru x O7− δ Superconducting Phase [Elektronische Daten] [R. Awad, A. Abou-Aly, S. Mahmoud, M. Barakat] Bulk superconducting samples of type GdBa2Cu3−x Ru x O7−δ , Gd-123, with x=0.0-0.3 were prepared by the conventional solid-state reaction technique. X-ray powder diffraction (XRD), scanning electron microscope (SEM), electron dispersive X-ray (EDX) and electrical-resistivity measurements were performed in order to investigate the effect of Ru4+ ions substitution on Gd-123 phase. Enhancement of both phase formation and the superconducting transition temperature T c for GdBa2Cu3−x Ru x O7−δ phase up to x=0.05 was observed from XRD and electrical-resistivity measurement, respectively. This enhancement was confirmed with the calculated relative volume fraction. For x>0.05, suppression of both phase formation and T c was obtained and the superconductivity was completely destroyed around x=0.3. The normal-state electrical resistivity was analyzed by the two- and three-dimensional variable range hopping (2D-VRH and 3D-VRH) and Coulomb gap CG. The results showed that the dominant mechanism was CG for x≤0.075, while was 3D-VRH for x≥0.15. Springer Science+Business Media, LLC, 2011 Gd-123 nationallicence Ru substitution nationallicence Coulomb gap nationallicence Variable range hopping nationallicence Awad R. Physics Department, Faculty of Science, Alexandria University, Alexandria, Egypt aut Abou-Aly A. Physics Department, Faculty of Science, Alexandria University, Alexandria, Egypt aut Mahmoud S. Physics Department, Faculty of Science, Alexandria University, Alexandria, Egypt aut Barakat M. Physics Department, Faculty of Science, Alexandria University, Alexandria, Egypt aut Journal of Superconductivity and Novel Magnetism Springer US; http://www.springer-ny.com 24/8(2011-11-01), 2227-2236 1557-1939 24:8<2227 2011 24 10948 https://doi.org/10.1007/s10948-011-1187-4 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10948-011-1187-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Awad R. Physics Department, Faculty of Science, Alexandria University, Alexandria, Egypt aut NATIONALLICENCE 700 1- Abou-Aly A. Physics Department, Faculty of Science, Alexandria University, Alexandria, Egypt aut NATIONALLICENCE 700 1- Mahmoud S. Physics Department, Faculty of Science, Alexandria University, Alexandria, Egypt aut NATIONALLICENCE 700 1- Barakat M. Physics Department, Faculty of Science, Alexandria University, Alexandria, Egypt aut NATIONALLICENCE 773 0- Journal of Superconductivity and Novel Magnetism Springer US; http://www.springer-ny.com 24/8(2011-11-01), 2227-2236 1557-1939 24:8<2227 2011 24 10948 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer