TY - JOUR
T1 - Oxygen stoichiometry in Co-1212, Co-1222 and Co-1232 of the homologous series Co-12s2 of "category-B" layered copper oxides
AU - Karppinen, M.
AU - Awana, V. P.S.
AU - Morita, Y.
AU - Yamauchi, H.
N1 - Conference code: 15
PY - 2003/10
Y1 - 2003/10
N2 - The results of a systematic study on oxygen stoichiometry are reported for the first three members of the novel CoSr2(Y,Ce)sCu 2O5+2s±δ or Co-12s2 homologous series, i.e. Co-1212, Co-1222 and Co-1232 phases, with a SrO-CoO 1±δ-SrO-CuO2-(Y,Ce)-[O 2-(Y,Ce)]s-1-CuO2 layered structure. The oxygen content was precisely determined by two independent chemical techniques: coulometric Cu+/Cu2+ titration and iodometric titration. Furthermore, oxygen stability/tunability was investigated by means of oxygenative and reductive annealings carried out in a thermobalance. It was revealed that all the three phases are rather stoichiometric in oxygen content (δ ≈ 0) and stable against both oxygenative and reductive annealings. The present results provide us with an indication that the nominally oxygen-stoichiometric B-[O2-B]s-1 "fluorite block", the characteristic structural element for all layered copper oxides of "category-B" [H. Yamauchi, M. Karppinen, Superlatt. Microstructr. 21A (1997) 128], is non-tunable in terms of the oxygen content not only in the Co-12s2 (s > 1) phases but also in other category-B phases.
AB - The results of a systematic study on oxygen stoichiometry are reported for the first three members of the novel CoSr2(Y,Ce)sCu 2O5+2s±δ or Co-12s2 homologous series, i.e. Co-1212, Co-1222 and Co-1232 phases, with a SrO-CoO 1±δ-SrO-CuO2-(Y,Ce)-[O 2-(Y,Ce)]s-1-CuO2 layered structure. The oxygen content was precisely determined by two independent chemical techniques: coulometric Cu+/Cu2+ titration and iodometric titration. Furthermore, oxygen stability/tunability was investigated by means of oxygenative and reductive annealings carried out in a thermobalance. It was revealed that all the three phases are rather stoichiometric in oxygen content (δ ≈ 0) and stable against both oxygenative and reductive annealings. The present results provide us with an indication that the nominally oxygen-stoichiometric B-[O2-B]s-1 "fluorite block", the characteristic structural element for all layered copper oxides of "category-B" [H. Yamauchi, M. Karppinen, Superlatt. Microstructr. 21A (1997) 128], is non-tunable in terms of the oxygen content not only in the Co-12s2 (s > 1) phases but also in other category-B phases.
KW - "Category-B" homologous series
KW - Co-based layered copper oxides
KW - Fluorite block
KW - Oxygen stoichiometry
UR - http://www.scopus.com/inward/record.url?scp=0042784978&partnerID=8YFLogxK
U2 - 10.1016/S0921-4534(03)01068-2
DO - 10.1016/S0921-4534(03)01068-2
M3 - Conference article
AN - SCOPUS:0042784978
VL - 392-396
SP - 82
EP - 86
JO - PHYSICA C: SUPERCONDUCTIVITY AND ITS APPLICATIONS
JF - PHYSICA C: SUPERCONDUCTIVITY AND ITS APPLICATIONS
SN - 0921-4534
IS - PART 1
T2 - International Symposium on Superconductivity
Y2 - 11 November 2002 through 13 November 2002
ER -