Effects of Fe3O4 Nano Particles Addition in High Temperature Superconductor YBa2Cu3O7-δ

Abstract

The effects of nano particles Fe3O4 addition on the superconducting and transport properties of YBa2Cu3O7-δ (YBCO) were studied. YBa2Cu3O7-δ superconductor powders were prepared by using high purity oxide powders via solid state reaction method. Nano Fe3O4 with 0.01 – 0.05 wt.% with average size 28 nm was added into YBCO. The transition temperatures (Tc) of the samples were measured by using four point probe method. The critical current (Ic) of the samples has been determined by using the 1 μV/cm criterion from 30 – 77 K. Sample with 0.02 wt.% nano Fe3O4 showed the highest Tc at 87 K. It is interesting to note the same sample also exhibited the highest Jc at 77 K up to 1683 mA/cm2. Nano Fe3O4 has acted as effective flux pinning centers in YBCO. A small amount of nano particles Fe3O4 addition has successfully improved the superconducting and transport properties of YBCO. The excessive addition of nano Fe3O4 (> 0.02 wt.%) suppressed the Tc and Jc. Overall, Jc decreases with increasing temperature (30 – 77 K) as a consequence of thermally activated flux creep. Magnetic impurities normally suppress superconductivity. However, by adding magnetic nano particles, current carrying capacity of superconductors YBCO was enhanced significantly.