Characteristics of high-performance BaHfO3-doped SmBa2Cu3Oy superconducting films fabricated with a seed layer and low-temperature growth

BaHfO3(BHO)-doped SmBa2Cu3Oy (SmBCO) superconducting films were fabricated with a seed layer and low-temperature growth (LTG technique) via pulsed laser deposition. The LTG technique enables the fabrication of high-quality SmBCO films even at a low substrate temperature during the deposition, and also greatly increases the number density of BHO nanorods. Transmission electron microscopy observations showed that the 5.6 vol% BHO-doped sample had a high number density [(4.8 +/- 0.3) x 10(3) mu m(-2)] of small (5.4 +/- 0.7 nm) BHO nanorods. This sample exhibits maximum flux pinning forces (F-p) of 405 GN m(-3) in 9.0 T at 40 K and 105 GN m(-3) in 9.0 T at 65 K. The high density and small size of the nano-rods in a REBa2Cu3Oy matrix (where RE is a rare earth element) is considered to be very effective for enhancing Fp at low temperatures under a high field.