置換固溶法による新しいペロブスカイト系高温超伝導体の設計

采用替代固溶法设计新型钙钛矿基高温超导体

• 批准号: 02227214
• 负责人: 荒井 弘通
• 金额: $ 1.28万
• 依托单位: Kyushu University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research on Priority Areas
• 财政年份: 1990
• 资助国家: 日本
• 起止时间: 1990 至 无数据
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-02227214/
• 关键词: YBa_2Cu_3O_<7ーy>; BaCuO_<2.5>; 置換固溶法; Y_<1ーx>Ba_<2+x>Cu_3O_<7ーy>; 高温超伝導体

若干の超伝導転移温度の上昇が認められたと前年度に報告したYBa_2Cu_3O_<7ーy>のCuサイトへのNb置換固溶体をCuに対する置換率(mol分率)x=0.01〜0.05の範囲で調製し、抵抗率および磁化率の温度依存性、ならびに粉末X線回折の測定を行なった。置換率が増加しても抵抗率測定における超伝導転移開始温度T_<Conset>はあまり変化せず、ゼロ抵抗温度T_<Czero>、交流磁化率測定における超伝導転移開始温度T_<Csus>の変化も小さい。粉末X線回折測定から求めた格子定数にも殆ど変化が見られず、他方、x≧0.01ではYBa_2NbO_6に帰属される新たな回折線が現われた。以上の結果からx=0.01がNbのCuサイトへの固溶限界であると思われる。BaCuO_<2.5>の金属元素組成は組成式Y_<1ーx>Ba_<2+x>Cu_3O_<7ーy>でのx=1に相当し、ヨウ素滴定から得られるCuの平均原子価は約3であるが、BaCuO_<2.5>の単一相は20K程度まで半導体で、交流磁化率測定からも完全反磁性への転移は全く認められなかった。YサイトへのBaの置換率xの増大の伴い各Tcは低下し、x=0.19ではT_<Conset>、T_<Czero>は消失し、交流磁化率測定における完全反磁性への転移幅も極めて小さくなった。この組成域でのX線回折パタ-ンにはBaCuO_2などに帰属される不純物ピ-クが多く見られ、YBCOの回折線強度は減少している。しかし、0.205≦x≦0.22では再び高いT_<Conset>、T_<Czero>、T_<Csus>が認められ、磁化率の転移幅もx=0.0と同程度となった。また、YBCO構造に帰属される回折線の強度が増大し、不純物相ピ-クが減少した。さらにxが増えると超伝導性は再び低下し、x≧0.3では超伝導転移は消失した。報告されている相図ではBaはYサイトに置換せずBaCuO_2を形成するとされているが、x=0.22近傍ではYサイトの置換率の増大にもかかわらずYBCO構造の分率が増大していると考えられ、この組成付近ではYサイトにBaが置換した新たな超伝導相の存在も示唆される。

The temperature rise of some superconductivity transition was observed in the previous year's report. The temperature dependence of resistivity and magnetic susceptibility, and the measurement of X-ray reflection of powders were studied. Substitution rate increase, resistivity measurement, transition start temperature T_(?), transition <Conset>resistance temperature T_<Czero>(?), AC susceptibility measurement, transition start temperature T_<Csus>(?) Powder X-ray reflection determination: find the grid fixed number, change the color, see the other, x ≥ 0.01, YBa_2NbO_6, belong to the new reflection line. The above results show that x=0.01 Nb Cu. The <2.5>elemental composition of BaCuO_is represented by the formula Y_&lt;1-x&gt;Ba_&lt;2+x&gt;Cu_3O_&lt;7-y&gt; x=1. The average atomic weight of Cu is about 3. The average atomic weight of BaCuO_is about 20 K. The average atomic weight of BaCuO_is about 3. The average atomic weight of Cu is about 3. The average atomic weight of BaCuO_is <2.5>about 20K. The average atomic weight of BaCuO_is about 3. The average atomic weight of Cu is about 3. The average atomic weight of BaCuO_is about 3. The average atomic weight of BaCuO_is about 3. The average atomic weight of Cu is about 3. The average atomic weight of BaCuO_is about 3. The average atomic weight of Cu is about 3. The average atomic weight of BaCuO_is about 20K. The average atomic weight of Cu is about 3. The average atomic weight of Cu is about 3 T_c decreases with the increase of substitution ratio x of Y_c and Ba. T_c decreases with x=0.19. <Conset>T_<Czero>c decreases with the increase of substitution ratio x of Y_c and Ba. T_c decreases with the increase of substitution ratio x of Y_c and Ba. T_c decreases with the increase of substitution ratio x of Y_c and Ba. The X-ray reflection intensity of BaCuO_2 and YBCO in the composition domain decreases due to the presence of impurities and the decrease of YBCO reflection intensity. T_<Conset>, T_<Czero>, T_<Csus>. The strength of the fold line in the YBCO structure increases and the impurity phase decreases. X is higher than X. X is lower than X is lower than X. X is lower than X is higher than X. X is lower than X is lower than X is. X is lower than X is higher than X is. X is lower than X is X is lower than X is. X is lower than X is X is lower than X is. X is lower than X is X is higher than X is. X is lower than X is higher than X is higher than X is. X is lower than X is higher than X is lower than X is. X is lower than X is lower than X is higher than X is. It is reported that the composition of BaCuO_2 and BaCuO_2 in YBCO increases with the increase of the substitution rate of BaCuO_2.

项目成果

KOICHI EGUCHI,KIMITAKA KUMA,AND HIROMICHI ARAI: "AN EFFECT OF SUBSTITUTION ON THE SUPERCONDUCTIVE PROPERTY IN PEROVSKITEーLIKE OXIDES" Molecular Crystals and Lizuid crystals. 184. 153-157 (1990)

KOICHI EGUCHI、KIMITAKA KUMA 和 HIROMICHI ARAI：“取代对类钙钛矿氧化物超导性能的影响”分子晶体和液体晶体 184. 153-157 (1990)。