Effects of Al2O3 nanoparticles on YBCO superconductor prepared using pyrophoric reaction

The objective of this work is to investigate the effect of Al
₂
O
₃
nanoparticles on structural and superconducting properties of YBa
₂
Cu
₃
O
_7-x
(YBCO) produced using pyrophoric reaction. A series of YBCO samples with small amounts (0 - 1.0 wt %) of nanosized Al
₂
O
₃
(- 10 nm) were characterized with XRD, and SEM measurements. Critical current J
_c
and critical temperature T
_c
measurements were performed using a standard four-probe technique at liquid nitrogen temperature. SEM analysis have shown that Al
₂
O
₃
nanoparticles was distributed along the grain boundaries which at higher wt % will reacts with the YBCO matrix to form Al rich spots intergrown within the YBCO superconducting matrix which then confirmed by XRD analysis. The incorporation of Al into YBCO structure slightly reduces the T
_c
. In spite of the decrease of the superconducting temperature T
_c
with increasing Al
₂
O
₃
nanoparticles addition, the J
_c
behavior is remarkably improved. The characteristic behavior of J
_c
can be explained in terms of the grains connectivity and recrystalization improvement.