O.A. Mironov

Band offsets in Eu-containing lead chalcogenides and lead chalcogenide superlattices from spectroscopic data

The results of an experimental study of the optical and photoelectrical properties of Eu-containing lead chalcogenides and superlattices are presented. From both sets of experiments band offset data for the lead chalcogenide-europium chalcogenide heterojunction are derived. The results are compared with the data obtained from a linear interpolation of the band structures between those of the binaries.

The galvanomagnetic properties of short-period SnTePbTe superlattices

Abstract (001) oriented SnTe PbTe superlattices (SLs) with the period in the range of 9–60 nm are grown. The temperature dependence of the conductivity, the Hall coefficient and the magnetoresistance anisotropy are investigated in the SLs in the temperature range of 1.5–300 K and magnetic fields up to 1.5 T. The SLs are of n-type with the apparent electron concentration in the range of 1019–1020 cm−3. The type II band ordering is concluded for the SLs. Below 6 K the SLs exhibit superconductivity. The superconductivity is suggested to have a local character and to be associated with the strained pseudomorphic SnTe layers.

Oscillations and quantization of resistance at the temperature critical points of PbS-PbTe-PbS three-layer films on (001) KCl

Oscillations and a set of inflection points have been discovered in the temperature dependences of the resistance of single-crystal PbS-PbTe-PbS three-layer films on (001) KCl. Extrema and inflection points are observed at the temperatures (m/n)T0 (T0=5.238 K), and at these temperature critical points the resistance of the samples takes one of the values (p/q)RQ, where RQ=25812.8 Ω is the resistance quantum; and m, n, p, and q are integers.

HTSC-like superlattices PbTePbS microwave spectroscopy

Abstract For the first time magnetic field nonresonant microwave absorption at 9.4 GHz in the thin film superconductive superlattices (001) PbTePbS (Tc=5.5 K) was investigated. These superlattices may be considered as structural HTSC models. It was found that absorption in the superlattices has similar peculiarities to ones in HTSC thin films. The influence of modulating magnetic field on the conditions of formation of various hysteretic absorption signals was analysed.

Magnetic-field oscillations of the critical current and the pinning force in PbTe/PbS semiconductor superlattices and YBa2Cu3O7–δ films

The magnetic-field dependences of the critical current Ic and the pinning force Fp in single-crystal semiconductor PbTe/PbS superlattices on KCl and YBa2Cu3O7–δ films in magnetic fields oriented perpendicular to the plane of the samples or parallel to the current were investigated. Oscillations of Ic and Fp were observed for superlattices with a parallel orientation of the magnetic field and with two directions of the field for the YBa2Cu3O7–δ film. A model was proposed for the vortex structures which correspond to extrema of the pinning force in superlattices. It was shown that the single points (extrema and points of inflection) of the field dependences of Fp for superlattices and a YBa2Cu3O7–δ film appear for critical values of the magnetic field equal to Hcr = (p/q)H0, where p and q are integers, H0 = 838.37 Oe, and H0 = ch/π eR02 is determined by the length R0 = 88.607 nm, somewhat less than the reciprocal of the Rydberg constant R∞ = me4/πħ3c (R∞−1 = 91.127 nm). It was inferred on the basis of published data that the temperature and magnetic-field dependences of the properties of superlattices and HTSC materials follow general laws.

Anomalous anisotropic current-voltage characteristics and magnetic resistance of single crystals YBa2Cu3O7- delta

The anomalous anisotropic current-voltage characteristics (CVC) and magnetic resistance in the temperature range Delta T=1-1.5 K above TC=91.5 K in a single crystal. YBa2Cu2O7- delta were studied. The observed S-shape CVC and the resistivity increasing can be explained by repeated Andreev reflection at S-N boundary and reflection at twin contact.

The nature of magnetic field hysteretic microwave absorption in the HTSC thin films and HTSC models epitaxial superlattices PbTe-PbS

Abstract For the first time magnetic field nonresonant microwave absorption at 9.4 GHz in the thin film superconductive superlattices (001)PbTe-PbS ( T c =5,5 K ) was investigated. These superlattices may be considered as structural HTSC models. It was found that absorption in the superlattices has similar peculiarities to ones in HTSC thin films. The influence of modulating magnetic field, temperature and other factors on the conditions of formation of various hysteretic absorption signals were analysed.