Dislocation density and critical current density of Sm_1+xBa _2-xCu₃O_y films prepared by various fabrication processes

Dislocations are effective flux-pinning centers in REBa₂Cu ₃O_y films at a magnetic field. To investigate the relationship between critical current density (J_c) and dislocation density, we discussed the dislocations in conventional pulsed-laser-deposition (PLD)-SmBCO films, vapor-liquid-solid (VLS)-SmBCO films, and low-temperature growth (LTG)-SmBCO films. The LTG-SmBCO and VLS-SmBCO films showed high-J _c at low magnetic fields. From the observation of etch pits, we found that the LTG-SmBCO and VLS-SmBCO films had high-dislocation densities. We speculate that J_c at low-magnetic fields is affected by dislocation density. LTG is effective for increasing dislocation density without deteriorating crystallinity or superconducting properties.