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A F Volkov

Publications and source records attributed to A F Volkov.

8 recordsLinked to original sources
PubMed2006

Superconducting phase coherent electron transport in proximity conical ferromagnets.

We report superconducting phase-periodic conductance oscillations in ferromagnetic wires with interfaces to conventional superconductors. The ferromagnetic wires were made of Ho, a conical ferromagnet. The distance between the interfaces was much larger than the singlet superconducting penetration depth. We explain the observed oscillations as due to the long-range penetration of an unusual helical triplet component of the order parameter that is generated at the superconductor/ferromagnet interfaces and maintained by the intrinsic rotating magnetization of Ho.

Journal Article↗
PubMed2003

Odd triplet superconductivity in superconductor-ferromagnet multilayered structures.

We demonstrate that in multilayered superconductor-ferromagnet structures a noncollinear alignment of the magnetizations of different ferromagnetic layers generates a triplet superconducting condensate which is odd in frequency. This triplet condensate coexists in the superconductors with the conventional singlet one but decays very slowly in the ferromagnet, which should lead to a large Josephson effect between the superconductors separated by the ferromagnet. Depending on the mutual direction of the ferromagnetic moments, the Josephson coupling can be both of 0 and of pi type.

Journal Article↗
PubMed2001

Long-range proximity effects in superconductor-ferromagnet structures.

We analyze the proximity effect in a superconductor/ferromagnet (S/F) structure with a local inhomogeneity of the magnetization in the ferromagnet near the S/F interface. We demonstrate that not only the singlet but also the triplet component of the superconducting condensate is induced in the ferromagnet due to the proximity effect. The singlet component penetrates into the ferromagnet over a short length xi(h) = sqrt[D/h] ( h is the exchange field and D the diffusion coefficient), whereas the triplet component penetrates over a long length sqrt[D/epsilon] and leads to a significant increase of the ferromagnet conductance below the superconducting critical temperature Tc.

Journal Article↗
PubMed2001

Enhancement of the Josephson current by an exchange field in superconductor-ferromagnet structures.

We calculate the dc Josephson current for two superconductor/ferromagnet (S/F) bilayers separated by a thin insulating film. It is demonstrated that the critical Josephson current I(c) in the junction strongly depends on the relative orientation of the effective exchange field h of the bilayers. We found that in the case of an antiparallel orientation I(c) increases at low temperatures with increasing h and at zero temperature has a singularity when h equals the superconducting gap Delta. This striking behavior contrasts with the suppression of the critical current by the magnetic moments aligned in parallel and is an interesting new effect of the interplay between superconductors and ferromagnets.

Journal Article↗
PubMedDate not supplied

[Transport of x-ray contrast media in isolated target and nontarget cells].

It was found that the accumulation of 125I-bilignost by isolated hepatocytes as target cells is mediated by the saturated and unsaturated systems. In thymocytes as non-target cells no saturated system of 125I-bilignost absorption was detected. 125I-triombrast transport in isolated hepatocytes and thymocytes takes place by usual diffusion.

Absorption↗
PubMedDate not supplied

[Phenobarbital--an inducer of bilignost excretion with the bile in rats].

It was found that a preliminary administration of phenobarbital to rats caused an increase of the rate of 125I-bilignost excretion in the bile by 46.6% but reduced its half-life in the blood by 48.3% and its excretion in the urine by 46.4%. Phenobarbital decreased the rate of 125I-bilignost absorption by the liver slices and increased the rate of release from them.

Animals↗
PubMedDate not supplied

[Dynamics of bilignost distribution in different exposures of the body in white rats].

The dynamics of distribution of 125I- and 131I-bilignost in intact rats has been studied in experimental pathological condition of the liver. It has been shown that the cholecystographic radiographic contrast agent (RCA) bilignost is absorbed and accumulated mainly by the liver. This indicates that the preparation elicits a selective action with respect to the liver. Administration of 125I-bilignost in conjunction with the unlabeled cholecystographic agents bilignost and endografin induces competition for absorption by the liver, which distinguishes these preparations from the urographic agent cardiotrast decreasing accumulation of the label by the kidneys. Acute CCl4 poisoning of the animals results in a sharp decrease in the liver capacity for accumulation of 131I-bilignost and to a slight rise in the preparation kidney level. Three-day administration of phenobarbital to rats produces a considerable drop in 125I-bilignost level in all the organs tested, suggesting an enhanced RCA excretion from the body.

Acute Disease↗