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The current–phase relation (CPR) of a YBa2Cu3Ox Josephson junction (JJ) on a bicrystal sapphire substrate was determined using the dependences of the amplitudes of the harmonic and subharmonic Shapiro steps and the critical current dependences of the DC-SQUIDs on external magnetic field. The deviations of CPR from sinusoidal one, caused by asymmetric dc biasing, result in an appearance of subharmonic Shapiro steps and in asymmetric shape of the SQUID modulation of the Ic(H) dependence. Precise measurements suppose sinusoidal CPR for symmetrical bicrystal junctions, while for asymmetric current flow in JJ the contribution of second harmonic in CPR increases monotonously. [Copyright &y& Elsevier]

Experimental results for DC interferometers of asymmetric topology with high-Tc bicrystal Josephson junctions are reported. Model of the tilted bicrystal junctions is discussed. As a model, parallel array of alternating `0'' and `π'' contacts was studied numerically. It has been shown that the array can act as either 0- or π-junction. Both the array characteristics and the critical current dependence on applied magnetic field for the array and DC interferometer are discussed. [Copyright &y& Elsevier]

The π-junction superconducting circuit dynamics was studied by means of numerical simulation technique. Parallel arrays consisting of Josephson junctions of both 0- and π-type were studied as a model of high-Tc grain-boundary Josephson junction. The array dynamics and the critical current dependence on magnetic field are discussed. Experimental results for dc interferometers with 0 and π high-Tc bi-crystal Josephson junctions are reported and discussed in comparison with numerical simulation. [Copyright &y& Elsevier]