Bicvystal Josephson junctions and direct current superconducting quantum inter ference devices(dc sQUIDs)were prepared on YBa_(2)Cu_(3)O_(7)(YBCO)thin films deposited on yttrium stabilized ZrO_(2) bicrystal substrates.The critical current densities J_(c)~2×10^(6)/cm^(2) for YBCO thin filmand(1-3)×10^(3)A/cm^(2) at boundaries were obtained at 77 K.For YBCO Josephson junctionmade on 28° misorientated boundary,the Shapiro steps were observed.The dc SQUID was madeon the 32° misorientated boundary junctions,which consisted of 40×40 m of loop and 2000×2000 pn planar superconductive flu.r focuser.The zoltage modulation depth of this SQUID was6 p.V,and the magnetic field sensitivity was estimated to be~2 pT/√Hz from the measurednoise level.
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