Sm/Ba組成比がSm1+xBa2-xCu3Oy薄膜の磁場中Jc特性に及ぼす影響

We have reported the superconducting properties of Sm1+xBa2-xCu3Oy (SmBCO; x=0.08) thin films prepared by the low-temperature growth (LTG) technique. To investigate the effect of the Sm/Ba composition ratio (x) in the SmBCO, we deposited an upper layer with the Sm/Ba composition of x=0.00-0.12. From the result of the etch pit and composition analysis, we found that the Sm/Ba composition ratio in the SmBCO film influenced possible pinning centers, such as linear defects including screw dislocation and edge dislocation, and nano-size low-critical temperature (Tc) phase acting as a field-induced pinning center. Moreover, we noticed the Sm/Ba composition ratio in the SmBCO film influenced Tc and critical current density (Jc). As a result, the SmBCO films with x=0.04 and 0.08 showed Jc=2.8 × 105 A/cm 2 and 1.7 × 105 A/cm2 (77 K, B//c, 8 T), respectively.