Ga. Daniels et al., Improved strong magnetic field performance of low angle grain boundaries of calcium and oxygen overdoped YBa2Cu3Ox, APPL PHYS L, 77(20), 2000, pp. 3251-3253
Critical currents and extended voltage-current characteristics of [001] til
t, low angle boundaries in thin film bicrystals of pure YBa2Cu3Ox and Y0.7C
a0.3Ba2Cu3Ox in strong magnetic fields (H < 10 T) have been measured. For 5
degrees [001] tilt boundaries, there are clear benefits to Ca additions, p
articularly when the sample is oxygen treated to further overdope the sampl
e after growth. Ca-doping decreases excess grain boundary resistance and di
minishes the gap between inter- and intragrain current density over a wide
field and temperature range. In spite of the lower T-c of the 0.3 Ca-doped
samples, Ca doping increases the intergrain critical current density at 44
K as high as 30% over 0-3 T and threefold at 5 T. (C) 2000 American Institu
te of Physics. [S0003-6951(00)03644-5].