The preparation of c-axis epitaxial Bi-2212 films on STO(100) by sol-gel method

Structural and morphological characterization of YBa2Cu3O7-x films deposited by screen printing from YBa2Cu3O6.962 superconductor in bulk

YBa2Cu3O7 melt textured thick films grown by infiltration process on YSZ substrate prepared by sol–gel method

A high-critical temperature superconductor (HTS) is ideal for use as an RF electromagnetic shield. As one of the basic areas of research for the improvement of the electromagnetic environment by the use of a bulk HTS as an electromagnetic shield, the present paper has applied a Bi-Pb-Sr-Ca-Cu-O (BPSCCO) plate to the far field region. In the frequency region from 1 to 30 MHz, however, the RF magnetic shielding degree SDH, with an average value of approximately 30 dB for the single BPSCCO plate, is not sufficient enough to shield electromagnetic waves. Accordingly, the present research has improved the frequency characteristics of SDH for the single BPSCCO plate to realize shielding over a broadband frequency region of 1 MHz to 3 GHz by the superposition of two ferrite plates over a BPSCCO plate; termed the sandwiched plate. The frequency characteristics of SDH for the sandwiched plate was improved by an average value of approximately 30 dB over the frequency region of 1 to 30 MHz. Experimental results revealed several characteristics of the sandwiched plate, which include the value of SDH as a function of radio frequency, and the non-dependence of SDH on the value of RF output power.

Improvement in the frequency characteristics of RF magnetic shielding: effects of the superposition of two ferrite plates over a BPSCCO plate

In this study, a set of self-consistent coupled-integral equations for the local magnetic flux and current distributions in a finite superconducting hollow cylinder under an axial magnetic field has been directly derived by using the Biot-Savart law within the framework of the critical-state model. The equations were first solved numerically in the three-dimensional space before obtaining the hysteresis loops for the Kim and Exponential models. We have assumed the contribution of the flux penetration from the inner surface of the sample to be higher than that of other surfaces. It is found that the variation in the area of lateral surface changes the magnitude of the magnetic moment of the finite hollow cylinder in the applied magnetic field. The obtained results are in good agreement with calculates. The formalism presented here can be used for an arbitrary shape of the superconducting system in the presence of any magnetic field dependence of the critical current density Jc(B) in an external magnetic field of arbitrary direction.

https://jitf.alzahra.ac.ir/article_4759_e7e7e198e1c22b682b3a0cca3f1447d7.pdf

Three-dimensional calculations of the magnetic fields in a finite superconducting hollow cylinder in an applied axial magnetic field

Shielding elements were made of bulk material or thick films. The bulk route is determined by large-scale processing. After an axial or isostatic pressing of the fine-grained powder composed of BSCCO, Y-123 and Nd-123, the material was sintered/textured and annealed in special programs. Then the characterization of the materials and a measurement of magnetic fields was done with the help of a specially constructed measuring apparatus with Hall- and SQUID-sensors. The objective of the thick film route was to get large, coated superconducting work pieces of YBCO and BSCCO (plates or cylinders) with current density of >1000 kA/cm 2 (and/or a shielding effect of >1 mT). Thick films were made by plasma spraying and paste technology. Substrates used were ZrO 2 , MgO, SrTiO 3 , BaZrO 3 and others. In some cases the work pieces were treated with laser radiation. After laser and thermal treatment the surface was more dense, the cracks were cured and the current density was increased by more than two times.

A. Buev

Papers

Superconducting materials for electronic applications

Preparation and Characterisation of HTSC Powders, Shaping of Bulk Materials and Their Magnetic Properties