HIGH-T_c SUPERCONDUCTING THIN-FILM WEAK LINKS: JOSEPHSON EFFECT AND MACROSCOPIC QUANTUM INTERFERENCE AT 4 K AND 77 K

Photoresponse beyond the red border of the internal photoeffect: designing problems of photon counting schemes in 10μm band

“…(where ℓ≈1 mm -height of paramagnetic adsorber; B r =0.01T -residual paramagnetic's field [22]; μ 0 =4π×10 -7 H/m -vacuum permeability δΦ≈5×10 -6 Ф 0 /√Hz -resolution of the quantum interferometer [23][24][25] in terms of quantum of magnetic flux Ф 0 =πħ/e≈2,07×10 -15 Wb ) corresponds to the bolometric response. Whereby the detector of this type can not be used in pulsed radar systems because of the considerable time of "thermal lag".…”

“…SQUID [23][24][25]), connected with the antiferromagnetic film of thickness z≈10μm, will be approximately 3×10 -5 flux quanta. In order to determine the required sensitivity of the magnetometer, the response δφ ≈3×10 -5 Φ 0 should be normalized by the square root of the frequency band width δf≈1/τ, providing temporary resolution τ≈1ns (corresponding to the distance resolution δℓ=cτ/2≈15sm).…”

“…be of the order of 10 microns (d≥λ). Thus a fragment of antiferromagnetic film will have approximately the same size as the working ring of DC-SQUID (which included a pair of "phase-sensitive" Josephson tunnel junction [23,24,[29][30][31], fig 6). This allows us to provide magnetic coupling of the film with the quantum interferometer (via a superconducting flux transformer) with nearly 100% transfer coefficient, while when this ratio is usually less than 1% (because of "mismatch" sizes) and "own" sensitivity of 10 -6 Ф 0 /√Hz deteriorates by 2 or more orders.…”

“…Operation of the system SQUID / magnetic adsorber rests upon functioning of SQUID, based upon Josephson effect [23,24,[29][30][31]. At the same time ultra high sensitive microwave radiation detectors, the operation of which is based upon Josephson effect "directly", are well known.…”