EM Radiation Sensor: Bulk SQUID Made from Polycrystalline HTSC

Abstract

The micro-contacts in the granules of the high-temperature superconductor (HTSC) films and other polycrystalline objects after transition to the SC state would then be similar to a bulk superconducting quantum interference device (SQUID), with the point S-N-S state greatly enhancing the sensitivity to electromagnetic radiation and can be used as of the application for much higher resolution than ever before possible (Braginsky, NATO ASI Series, 329, 235 (1996); Bray, J. Supercond. Novel Magn., 21, 335–341 (2008); Cantor, Supercoduct. & Cryoelectronics, 2000). Production of SQUIDs based on thin films is a very complicated technological process, requiring very expensive equipment. Use of the composite (HTSC powder + epoxy matrix), compressed SC powder, and thick films for SQUID fabrication should be very much simpler. The range of frequencies that can by detected with such a device will depend on the circuit parameters and may be extended to the microwave or infrared regimes (Braginsky, NATO ASI Series, 329, 235 (1996); Jurga et al. Acta Phys Pol A, 114, (2007); Jurga et al., Acta Phys Pol A, 114, (2007)). The advantage of the bulk SQUID based on HTSC-YBa2Cu3Ox, BiSr2Ca2Cu3OX, B(Pb)iSr2Ca2Cu3OX, and NdBaCoX (powder + epoxy matrix, compressed SC powders, and thick films) is the non-selective nature of the spectral characteristics over a wide frequency range, high sensitivity, and quick response. For suppressing the large noise resulting from the maximal instability of electromagnetic properties at the SC, insulator transition is employed a differentiation procedure of the measurements signal.