REBa2Cu3O7-δ (REBCO, RE - rare earth elements) superconductors are considered to be the most promising candidates due to their high superconducting transition temperature (Tc) of ~92 K and superior flux pining ability for various practical applications. For further improving the field dependence properties of REBCO superconductors, integrating new methodologies are necessary. Among, improvement of the critical current density (Jc) is crucial for developing next-generation applications. The magnitude of Jc depends on how much the motion of the magnetic flux can be prevented against the Lorentz force which creates the lower energy. This can be achieved by dispersing normal-conductive such as RE2BaCuO5 (RE211) particles, other defects which are of nano-metric size in the superconducting matrix. Recently, we demonstrated the integration of high-energy ultrasonic irradiation to the YBCO superconductors which effectively improved Jc and trapped fields. In the present work, we discuss the study of ultrasonication irradiation effect on the growth and superconducting properties of top-seeded melt grown bulk YBCO single grains (YBCO-U). Ultrasonic power of 450 W was employed for 30 min to create the sharp-edged, individual, and nano-meter sized Y211 phase particles. Systematic isothermal experiments were conducted at various temperatures to understand the effect of 30 wt.% ultrasonicated Y211 particles addition on the growth-mechanism of YBCO-U bulk single grain superconductors. The microstructural features of the YBCO-U sample indicated that the inclusion of 2 differently sized Y211 phase particles in the bulk samples.Y211 particles of ~10 µm size generated due to conventional peritectic melting and ~100 nm-sized due to the addition of ultrasonically pre-treated precursor powders. YBCO bulks grown by the addition of ultrasonically pre-treated Y211 resulted in homogenous dispersion of fine-sized 211 particles and improving the growth rate due to improved peritectic reaction. The self-field Jc of ultrasonically produced YBCO is 97 kA/cm2 at 77 K and which is about 2 times larger than the conventional method. We demonstrate that the addition of sharp-edged 211 particles addition improved the growth and Jc of the YBCO single grains. The present method is reliable and cost-effective and free from any chemical contamination.
Keywords: REBa2Cu3O7-δ single grain, Ultrasonic Irradiation, Crystal growth, Critical current density