Abstract
To obtain useful information on how to improve the irreversibility field Hirr and critical current density Jc in RE123 systems, the critical current properties of Nd1+xBa2-xCu3O7+δ(Nd123) have been studied. Various parameters, such as partial pressure of oxygen P(O2) during the growth of single crystals, the influence of post-annealing at 900‣ and quenching under different P(O2), the oxygen annealing under high P(O2) and element-substitution into the crystals, were systematically changed. On special notice is that Hirr of the Nd123 single crystal was remarkably increased by partial substitution of Ca for the Nd-site up to 13.3 T at 77 K.
