YBa/sub 2/Cu/sub 3/O/sub X/ submicron Josephson junctions on bicrystal substrates

A technological process based on e-beam lithography and ion beam etching of YBa/sub 2/Cu/sub 3/O/sub X/ (YBCO) film through carbon mask is applied to fabricate a series of YBCO dc SQUIDs on SrTiO/sub 3/ 30(degree)-bicrystal substrates. The width of Josephson junctions used in SQUIDs ranges from 0.6 (mu)m to 1 (mu)m. The character of the temperature dependence of the junctions critical current enables one to confirm the realization of d-wave pairing mechanism as well as the presence of localized states in the grain boundary region. The diffraction pattern of submicron junctions is discussed in relation to their further application in SQUIDs for task of scanning SQUID microscopy in high magnetic fields.