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1.
The voltage response of a thin-film normal-metal hot-electron bolometer based on a SINIS (superconductor-insulator-normal metal-insulator-superconductor) structure to the radiation of a high-temperature Josephson junction in the terahertz frequency region was measured. Bolometers were integrated with planar log-periodic and double-dipole antennas, and Josephson junctions were integrated with log-periodic antennas. Measurements showed that the Josephson junction at a temperature of 260 mK was overheated by the transport current, so that its electron temperature exceeded 3 K at a bias voltage of 1 mV. The maximum response of a bolometer with a double-dipole antenna was observed at a frequency of 300 GHz, which agreed well with the calculated value. The Josephson radiation was observed at frequencies up to 1.7 THz. The voltage response of a bolometer reached 4×108 V/W, and the total noise-equivalent power reached 1.5×10?17 W/Hz1/2.  相似文献   
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We report on a successful attempt to fabricate a Coulomb blockade electrometer consisting of an ultrasmall YBa2Cu3O7−δ (YBCO) island coupled to two gold electrodes through a high-resistance native surface tunnel barrier. A third electrode placed near the island was used as an electrostatic gate. Spectra typical for tunneling into the YBCO superconductor were reproducibly measured. At temperatures below 0.5 K the low-bias conductance was suppressed by the Coulomb blockade. The blockade could be periodically varied by the gate potential. An external magnetic field of up to 5 T strongly influenced the transport via the island but without any change in the period of the Coulomb oscillations. Pis’ma Zh. éksp. Teor. Fiz. 63, No. 2, 112–117 (25 January 1996) Published in English in the original Russian journal. Edited by Steve Torstveit.  相似文献   
3.
To investigate the appearance of localized phonon modes, superconductive tunneling was performed into films of Pb0·9M0·1 (M = Ag, Cd, Ga, Ge, In, Mg, Mg, Sb, Sn, Te, Zn) and Pb0·97Sn0·03. The films were quench-condensed and later annealed at 30, 100 and 300°K. Structure in tunneling curves resulting from localized phonons was observed only for a well annealed In alloy film. For most of the impurities an absence of observable local phonon modes could be explained as due to a lack of solid solubility or of sufficient structural order in the film. For Na and Sn alloys, however, these arguments cannot be used. No modes could be seen for such alloys even in films condensed at room temperature, heat-treated slightly, and quenched directly into liquid helium.  相似文献   
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Superconducting transition temperatures (T c) and electron tunneling characteristics have been measured on amorphous, vapour quenched films of Ga and Bi in the thickness range 3 to 50 nm. TheT c's are depressed and the tunnel densities of states are smeared as compared to bulk superconductors. A model considering the proximity effect between an extremely thin non-superconducting sheath (presumably due to the decrease of electron concentration at the surfaces) and a remaining bulk superconducting part gives good agreement withT c measurements, while the predicted tunnel density of states is only in qualitative correspondence with experiments.  相似文献   
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The behavior of the electrical resistivity and magnetoresistance of 40-to 120-nm-thick La0.67Ca0.33MnO3 films grown on differently oriented lanthanum aluminate substrates was studied. The cell volume in thin (40 nm) La0.67Ca0.33MnO3 films grown coherently on (001)LaAlO3 was found to be substantially smaller. Mechanical stress relaxation in biaxially strained La0.67Ca0.33MnO3 films is accompanied by an increase in the cell volume. The temperatures at which the electrical resistivity and magnetoresistance in biaxially strained La0.67Ca0.33MnO3 films were maximum can differ by 60–70 K from those observed in bulk single crystals.  相似文献   
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Many highTcsystems exhibit structural distortions or anomalies, some of which correlate withTc. We present our results for three such systems and discuss them in the context of providing any evidence for coupling of the lattice to the superconducting pairs. We then propose a modulation type of experiment that should provide unambiguous results if a significant lattice-pair coupling does exist.  相似文献   
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