caa a22 4500 463231902 CHVBK 20180405153244.0 cr unu---uuuuu 170326e20070101xx s 000 0 eng 10.1007/s10853-006-1137-x doi (NATIONALLICENCE)springer-10.1007/s10853-006-1137-x Unusual magnetic and transport properties of the CMR Pr1− x Ca x MnO3− y system [Elektronische Daten] [Ri-Zhu Yin, Chul Yo] The substituted nonstoichiometric perovskite Pr1−x Ca x MnO3−y compounds have been synthesized by a standard combustion technique, which show uniphase solid solutions. The all samples of the Pr1−x Ca x MnO3−y system show an orthorhombic crystal system and the cell volumes are decreased with increasing the larger amounts of substituted atoms or the increasing x values. The mixed valence of Mn ions is identified by the XAS (XANES/EXAFS) spectroscopy and the amounts of Mn4+ ions are determined by an iodometric titration method. Nonstoichiometric chemical formulas of the Pr1−x Ca x Mn 1−τ 3+ Mn τ 4+ O3−y compounds have been obviously formulated. Magnetic properties are investigated by SQUID and thus the Pr1−x Ca x MnO3−y (x=0.4, 0.6, and 0.8) compounds show the transition from antiferromagnetic state to paramagnetic state. The Pr1−x Ca x MnO3−y (x=0.0, 0.2, and 1.0) compounds show the transition from ferromagnetic state to paramagnetic state. The facts that Mn4+ contents play important roles in the magnetic ordering have been found out. The transport properties have been studied by the DC electrical conductivity measurement under magnetic fields of 0G and 3kG. Maximum and minimum MR ratios are 1016% of the Pr0.6Ca0.4MnO2.846, and −77.5% of the PrMnO3.021 compound, respectively. Springer Science+Business Media, LLC, 2006 Yin Ri-Zhu Department of Chemistry, Yonsei University, 120-749, Seoul, South Korea aut Yo Chul Department of Chemistry, Yonsei University, 120-749, Seoul, South Korea aut Journal of Materials Science Kluwer Academic Publishers-Plenum Publishers; http://www.springer-ny.com 42/2(2007-01-01), 660-668 0022-2461 42:2<660 2007 42 10853 https://doi.org/10.1007/s10853-006-1137-x text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10853-006-1137-x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Yin Ri-Zhu Department of Chemistry, Yonsei University, 120-749, Seoul, South Korea aut NATIONALLICENCE 700 1- Yo Chul Department of Chemistry, Yonsei University, 120-749, Seoul, South Korea aut NATIONALLICENCE 773 0- Journal of Materials Science Kluwer Academic Publishers-Plenum Publishers; http://www.springer-ny.com 42/2(2007-01-01), 660-668 0022-2461 42:2<660 2007 42 10853 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer