Syuji Moriya

Pd addition in high Tc YBaCuO oxide

Abstract A small amount of Pd addition increases T c for the YBa 2 Cu 3 O 7− y oxide. The maximum offset, midpoint and onset temperatures of the YBa 2 (Cu 0.999 Pd 0.001 ) 3 O 7− y oxide are 92.1, 95.0 and 105 K, respectively. Excess addition of Pd decreases T c . The T c change is consistent with the results of the lattice constants.

Formation temperature of bosons in high-Tc YBa2Cu3O7−y systems

AbstractAt different equilibrium temperatures, a precise measurement of the electrical resistivity (R) is performed for high Tc polycrystalline YBa2Cu3O7−y systems. T2 law is applied in the part of the R-T relationship far above the superconducting transition temperature. Since Landau and Pomeranchuk predicted the T2 law arising from electron-electron scattering, a higher critical temperature of T2 law is defined as a start point (Tes) of electron-electron scattering. On the other hand, we defined a lower critical temperature of T2 law as the formation temperature (Tee) of an electron-electron pair, i.e. the formation temperature of boson. Tee relates to the offset temperature of the superconducting transition

Aging induced high Tc of Ar ion-implanted YBa2Cu3O7−y

({\rm T}_{{\text{C}}_{{\text{off}}} } )

Titanium addition in the highTc Y-Ba-Cu-O oxide

.

Rapid rate of ion milling for the highTc YBa2Cu3O7−y system

N 2 implantation increases T c under low acceleration energy for high T c YBa 2 Cu 3 O x . The maximum value of T coff is shown at 500 sec of the implantation time. The influence of the current density on T coff is obtained. T coff of the implanted sample above 5 mA mm −2 of the current density remarkably approaches that before the implantation. The maximum T coff value and its increase by N 2 implantation are 96.8 K and 4.1 K at 5×10 −3 mA mm −2 of the detectable minimum current density

Effect of argon ion implantatation onTc for the YBa2Cu3O7−y system

Abstract Since excess Ar ion-implantation tremendously decreases T c , a recovering process is investigated for high T c YBa 2 Cu 3 O 7 − y .Aging recovers T c of the excess implanted specimens. It is especially that T c increases beyond the value before implantation. Th maximum increased value of the offset temperature is 3.3 K. Excess aging decreases T c . The T c value of the recovered sample approaches that before the implantation. The apparent activation energy of the recovered process is 121 kJ/mole. It approximately agrees with the activation energy of the oxygen diffusivity in YBa 2 Cu 3 O 7− y .