Critical current enhancement by neutron irradiation of rapidly textured Bi2Sr2CaCu2O8

摘要

We have investigated the effect of fast neutron irradiation on c-axis aligned Bi(sub 2)Sr(sub 2)CaCU(sub 2)O(sub 8) (Bi2212) produced using a new technique. Amorphous Bi2212 was crystallized under 20 MPa uniaxial stress at 870(degree)C for 6 hrs. DC SQUID shows a transition onset of 90K. Material was cut into 2 (times) 2 (times) 0.150 mm slabs, sealed in quartz ampules, and irradiated at fluences of 10(sup 16), 5 (times) 10(sup 16), 2.5 (times) l0(sup 17), and 7.2 (times) 10(sup l7) n/cm(sup 2). DC SQUID results show that J(sub c) is increased by a factor of 2.5 at 10K for fluences of 7.2 (times) l0(sup 17) for H parallel to c-axis for fields less than 3 T. The higher the fluence, the lower the dependency of J(sub c) on applied field and temperature. T(sub c) decreased by 1 K for a fluence of 2..5 (times) l0(sup 17) n/cm(sup 2) with an additional 2 K drop for 7.2 (times) l0(sup 17) n/cm(sup 2). The increase in the width of the high field hysteresis loops for increasing fluence is more pronounced for samples measured normal to the c-axis.