Effect of Different Nano-sized MgO Addition on YBa2Cu3O7-δ Superconductor

The effect of nanoparticle with different size on a superconductor is interesting because the size of the coherence length, penetration depth, and the magnetic flux in a superconductor is in the nanometer range. In this paper, we report the effects of different nano-sized MgO (20, 40, and 100 nm) addition on YBa 2 Cu 3 O 7-δ (MgO) x for x = 0, 0.1, and 0.2 wt.%. X-ray diffraction patterns indicated a single YBa 2 Cu 3 O 7 (YBCO) phase where the peaks were shifted to larger angles in the 20- and 40-nm MgO-added samples indicating induced stress of first order in the structure. The electrical resistance versus temperature was measured using the four-probe method. The transition temperature, T c , for the pure YBCO showed T c = 90 K and was suppressed to 78–80 K for the 20- and 40-nm MgO-added samples. AC susceptibility ( χ = χ ′ + i χ ″) measurements showed a shift in the peak temperature, T p , of the imaginary susceptibility χ″ towards lower temperatures for 20-nm MgO-added samples but increased with larger MgO (100 nm). This work showed that smaller nano-sized MgO suppressed the superconducting properties of YBCO more compared with the larger MgO.