Yuichiro Kita

HighTc of liquid-quenched Bi1.6Pb0.4Sr2Ga2Cu3Ox

AlthoughTc cannot be found for a liquid-quenched Bi1.6Pb0.4Sr2Ca2Cu3Ox glassy sample, a highTc is found after annealing for 24 h at 1100 K. The maximum offset temperature of the superconducting transition is 113.3 K at 2.2 × 10−2mAmm−2. The maximumTcoff is larger than that (the maximumTcoff is 103.4 K at 2.0 × 10−2 mAmm−2) of sintered specimens before liquid quenching.

Abnormal Tc change of Bi1.6Pb0.4Sr2Ca2(Cu1−zTiz)3Ox (0.01<z<0.1)

Influence of Ti addition (substitution for Cu) on Tc is studied for high Tc Bi1.6Pb0.4Sr2Ca2(Cu1−zTiz)3Ox. An abnormal Tc change is found between z=0.01 and 0.1. Based on results of the electrical resistivity and x‐ray diffraction, the abnormal Tc change is discussed.

Cooling rate dependence of abnormal Jc near the boiling point of nitrogen for YBa2Cu3O7-y

Abstract The cooling rate ( R ) dependence of J c is investigated for high T c YBa 2 Cu 3 O 7- y . J c ( J c 60 K , J c 70 K and J c 80 K ) at different temperatures depends on R . We show the existence of an approximately linear relationship between superconductive values ( J c 60 K , J c 70 K and J c 80 K ) and R .

Influence of Ti addition on Tc of Bi1.6Pb0.4Sr2Ca2Cu3Ox

Abstract Dependences of Ti addition on T off c are investigated for Bi 1.6 Pb 0.4 Sr 2 Ca 2 Cu 3 O x . Limits of Ti addition ( (compositional substitution for Cu, Pb, Bi, Sr and Ca) to maintain the high T off c are defined. Using the X-ray diffraction and electrical results, the dependences of Ti addition on T off c are discussed.

Compressive-stress-induced T c increase of the low- T c Bi 1.6 Pb 0.4 Sr 2 Ca 2 Cu 3 O x phase

The effect of compressive stress on {ital T}{sub {ital c}} is studied for the low-{ital T}{sub {ital c}} Bi{sub 1.6}Pb{sub 0.4}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub {ital x}} phase. Although stress decreases the {ital T}{sub {ital c}} of the high-{ital T}{sub {ital c}} sample, the small compressive stress increases the {ital T}{sub {ital c}} of the low-{ital T}{sub {ital c}} phase. The maximum {ital T}{sub {ital c}}{sup off} is about 113.6 K at 0.01 mA/mm{sup 2} (current density) and 3.92 N/mm{sup 2} of the low-{ital T}{sub {ital c}} phase where {ital T}{sub {ital c}}{sup off} is 96.2 K before loading. The maximum {ital T}{sub {ital c}}{sup off} is larger than the unloaded value (109.3 K) of the high-{ital T}{sub {ital c}} Bi{sub 1.6}Pb{sub 0.4}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub {ital x}} sample. Based on the results of x-ray-diffraction, electrical-resistivity, and Seebeck-effect measurements, the {ital T}{sub {ital c}} is dominated by carrier concentration and crystal perfection of the lattice ordering.

Compressive-stress-inducedTcincrease of the low-TcBi1.6Pb0.4Sr2Ca2Cu3Oxphase

The effect of compressive stress on {ital T}{sub {ital c}} is studied for the low-{ital T}{sub {ital c}} Bi{sub 1.6}Pb{sub 0.4}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub {ital x}} phase. Although stress decreases the {ital T}{sub {ital c}} of the high-{ital T}{sub {ital c}} sample, the small compressive stress increases the {ital T}{sub {ital c}} of the low-{ital T}{sub {ital c}} phase. The maximum {ital T}{sub {ital c}}{sup off} is about 113.6 K at 0.01 mA/mm{sup 2} (current density) and 3.92 N/mm{sup 2} of the low-{ital T}{sub {ital c}} phase where {ital T}{sub {ital c}}{sup off} is 96.2 K before loading. The maximum {ital T}{sub {ital c}}{sup off} is larger than the unloaded value (109.3 K) of the high-{ital T}{sub {ital c}} Bi{sub 1.6}Pb{sub 0.4}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub {ital x}} sample. Based on the results of x-ray-diffraction, electrical-resistivity, and Seebeck-effect measurements, the {ital T}{sub {ital c}} is dominated by carrier concentration and crystal perfection of the lattice ordering.

Compressive-stress-induced T sub c increase of the low- T sub c Bi sub 1. 6 Pb sub 0. 4 Sr sub 2 Ca sub 2 Cu sub 3 O sub x phase

The effect of compressive stress on {ital T}{sub {ital c}} is studied for the low-{ital T}{sub {ital c}} Bi{sub 1.6}Pb{sub 0.4}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub {ital x}} phase. Although stress decreases the {ital T}{sub {ital c}} of the high-{ital T}{sub {ital c}} sample, the small compressive stress increases the {ital T}{sub {ital c}} of the low-{ital T}{sub {ital c}} phase. The maximum {ital T}{sub {ital c}}{sup off} is about 113.6 K at 0.01 mA/mm{sup 2} (current density) and 3.92 N/mm{sup 2} of the low-{ital T}{sub {ital c}} phase where {ital T}{sub {ital c}}{sup off} is 96.2 K before loading. The maximum {ital T}{sub {ital c}}{sup off} is larger than the unloaded value (109.3 K) of the high-{ital T}{sub {ital c}} Bi{sub 1.6}Pb{sub 0.4}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub {ital x}} sample. Based on the results of x-ray-diffraction, electrical-resistivity, and Seebeck-effect measurements, the {ital T}{sub {ital c}} is dominated by carrier concentration and crystal perfection of the lattice ordering.