Pinning centers in YBa2Cu3O7−δ thick films prepared on Y2BaCuO5 substrates by the painting-on method

High-Tc rf SQUIDs with large inductance of quantization loop

“…Self-noise of HTS-based Josephson junction can be low enough; the higher the critical current density, the lower the self-noise. In YBCO systems, it is possible to achieve high values of the pinning force [3,4,20], which guarantees high values of critical current density in the ab-plane of a YBCO crystal cell, and an acceptably low level of excess 1/f noise as well. A theoretical estimate of the internal noise level and the maximum inductance of the RF SQUID quantization loop can be carried out in a simple way [10].…”

“…A modification of this technique by means of the melting-growing (MG) technology [2] allowed one to obtain the TFs with microscopic inclusions of the Y 2 BaCuO 5 -phase, which play the role of additional pinning centers in the YBa 2 Cu 3 O 7−δ -matrix [3]. Temperature and field dependency study of the AC susceptibility of these MG TF structures shows that pinning force is increased several times as compared with TF reference samples (without MG) which superconductive characteristics are similar to those of the samples synthesized by the conventional ceramic technique [3]. The high density (minimum porosity) is an important feature of the MG TFs, and determines higher stability of such structures against a degradation process.…”