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| 2. |
- Lombardi, Floriana, 1967, et al.
(författare)
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Quantum properties of d-wave YBa2Cu3O7-δ Josephson junction
- 2006
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Ingår i: Physica C: Superconductivity and its Applications. - : Elsevier BV. - 0921-4534. ; 435:1-2, s. 8-11
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Tidskriftsartikel (refereegranskat)abstract
- We have measured the transport properties of YBa2Cu3O7-δ (YBCO) dc SQUIDs with Josephson junctions characterized by a combination of 45° [0 0 1] tilt and α [1 0 0] tilt grain boundary with α = 0°, ±10° and 45°. By increasing the component of transport in the YBCO c-axis direction (increasing values of α), the SQUIDs showed an enhanced quality factor. At the same time, for all the devices the response under an external magnetic field presented the main features of an unconventional Josephson current phase relation with a pronounced sin 2 component. Switching current measurements at low temperature (10th of mK) also revealed that the dynamics of grain boundary junction resulting from a combination of 45° [0 0 1] and 45° [1 0 0] tilt is dominated by macroscopic quantum tunnelling of the superconductive phase. The features are quite encouraging for applications of d-wave junctions in quantum circuitry.
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| 3. |
- Stepantsov, Evgeni, 1951, et al.
(författare)
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Growth of twin-free b-oriented YBa2Cu3O7-x Films
- 2015
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Ingår i: Crystallography Reports. - : Pleiades Publishing Ltd. - 1562-689X .- 1063-7745. ; 60:3, s. 393-396
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Tidskriftsartikel (refereegranskat)abstract
- YBa2Cu3O7 - x films of b orientation have been grown on the surface of (100)SrLaGaO4 crystal. It is demonstrated that the films pass to the superconducting state at a temperature of 89 K. In the nonsuper-conducting region, the film resistance decreases linearly with a decrease in temperature at a rate of 30 Omega per 100A degrees C. According to the X-ray diffraction data on the crystallographic structure of the YBa2Cu3O7 - x films, they are single-crystal and b-oriented. It is shown that the films contain no domains of other crystallographic orientations, including a-oriented domains. Therefore, the films are free of structural twins.
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| 4. |
- Stepantsov, Evgeni, 1951, et al.
(författare)
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Growth of Ultrathin Twin-Free b-Oriented YBa2Cu3O7-x Films
- 2017
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Ingår i: Crystallography Reports. - : Pleiades Publishing Ltd. - 1562-689X .- 1063-7745. ; 62:1, s. 127-132
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Tidskriftsartikel (refereegranskat)abstract
- Twin-free b-oriented YBa2Cu3O7 - x films with a thickness less than 40 nm have been epitaxially grown on (100)SrLaGaO4 crystals. Based on the temperature dependence of resistance, the onset temperature of the transition to the superconducting state is found to be 90 K; the transition width is 4 K. The film growth has been performed in two stages. A (100)PrBa2Cu3O7 - x buffer layer was previously grown on a (100)SrLaGaO4 substrate by rf magnetron sputtering in an Ar-O-2 gas mixture at a continuous and monotonic increase in temperature from 660 to 830A degrees C. The main YBa2Cu3O7 - x film was grown on the buffer layer surface by pulsed laser deposition in an oxygen medium at a fixed temperature (800A degrees C). The above processes were implemented in different chambers, which were connected by a vacuum channel for transporting samples. Both films were grown in situ, without contacting atmosphere in all growth stages. An X-ray diffraction study has shown that the YBa2Cu3O7 - x films are single-crystal and free of precipitates of other phases and domains of other orientations.
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| 5. |
- Stepantsov, Evgeni, 1951, et al.
(författare)
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Growth of YBa2Cu3O7 films with 100 tilt of CuO planes to the surface on SrTiO3 crystals
- 2011
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Ingår i: Crystallography Reports. - : Pleiades Publishing Ltd. - 1562-689X .- 1063-7745. ; 56:1, s. 152-156
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Tidskriftsartikel (refereegranskat)abstract
- YBa2Cu3O7 films with CuO planes tilted to the surface have been grown on SrTiO3 crystals by pulsed laser deposition. The tilt angle was varied in the range from 0A degrees (CuO planes are parallel to the surface) to 70A degrees. At this tilt, the crystalline lattice of the film was rotated by rotating the substrate crystalline lattice around its axis [100], which is oriented parallel to the surface. The zero tilt of CuO planes corresponds to the orientation of the SrTiO3 surface parallel to the (100) plane. It is established that the CuO planes of the film remain parallel to one or several (100)-type planes of the substrate at an arbitrary tilt angle. In the range of tilt angles from 0A degrees to 41A degrees, the film has a single-crystal structure. At tilt angles above 41A degrees, the film is transformed into a two-domain texture and its surface roughness sharply increases.
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| 6. |
- Stepantsov, Evgeni, 1951, et al.
(författare)
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Growth of YBa2Cu3O7 films with [110] tilt of CuO planes to surface on SrTiO3 crystals
- 2013
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Ingår i: Crystallography Reports. - 1562-689X .- 1063-7745. ; 58:3, s. 488-492
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Tidskriftsartikel (refereegranskat)abstract
- YBa2Cu3O7 films with the CuO plane tilted to the surface have been grown on SrTiO3 crystalline substrates by pulsed laser deposition. This tilt was obtained by rotating the film lattice with respect to the substrate surface around its [110] axis oriented parallel to the surface. The zero tilt of the CuO plane was implemented at the orientation of the SrTiO3 crystal surface parallel to the (100) plane. The rotation angles were varied in the range from 0A degrees to 70A degrees. It is found that, being tilted at any angle, the CuO planes of the film remain parallel to one or several crystallographic planes of the (100)-type substrate. In the range of tilt angles from 0A degrees to 49A degrees, the film has a single-crystal structure. Above 49A degrees the film is transformed into a three-domain texture and its surface roughness sharply increases.
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| 7. |
- Stepantsov, Evgeni, 1951, et al.
(författare)
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Investigation into the growth and structure of thin-film solid solutions of iron-based superconductors in the FeSe0.92-FeSe0.5Te0.5 system
- 2013
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Ingår i: Crystallography Reports. - : Pleiades Publishing Ltd. - 1562-689X .- 1063-7745. ; 58:5, s. 735-738
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Tidskriftsartikel (refereegranskat)abstract
- Thin films of FeSe0.92 and FeSe0.5Te0.5 iron chalcogenide superconductors and solid solutions containing these components in different ratios have been grown on the surface of LaAlO3 (102) crystals by pulsed laser deposition. Films of solid solutions have been deposited by simultaneous laser ablation from two targets of the FeSe0.92 and FeSe0.5Te0.5 stoichiometric compositions onto one substrate. An X-ray diffraction study of the film structure shows that the films grown are epitaxial and their lattice parameters regularly vary with the ratio of the deposited components, which was controllably varied by changing the ablation intensities from the targets.
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| 8. |
- Sukhorukov, Y. P., et al.
(författare)
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Effect of an interface boundary on the magnetooptical and magnetotransport properties of La0.67Ca0.33MnO3/La0.67Sr0.33MnO3 heterostructures
- 2010
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Ingår i: Technical Physics. - 1063-7842 .- 1090-6525. ; 55:8, s. 1161-1167
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Tidskriftsartikel (refereegranskat)abstract
- The optical, magnetooptical (Kerr effect and magnetotransmission), and magnetotransport properties of La2/3Ca1/3MnO3/La2/3Sr1/3MnO3 and La2/3Ca1/3MnO3/SrTiO3/La2/3Sr1/3MnO3 heterostructures on SrTiO3 substrates are studied. The contribution of the interface boundary to the magnetotransmission is typical of a material with a transitional composition. It is found that a 2-nm-thick SrTiO3 spacer does not influence the shape and position of the magnetotransmission peak in a field normal to the surface of the heterostructure but increases the contribution of the upper layer to the magnetotransmission in the Voigt geometry and also enhances the magnetoresistance that is due to the tunneling of spin-polarized carriers through the spacer. The Kerr spectra taken of the heterostructures are typical of single-layer single-crystal films.
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| 9. |
- Sukhorukov, Y. P., et al.
(författare)
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Magnetorefractive and Kerr effects in the La0.67Ca0.33MnO3/La0.67Sr0.33MnO3 (n) superlattices
- 2014
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Ingår i: Superlattices and Microstructures. - : Elsevier BV. - 0749-6036 .- 1096-3677. ; 75, s. 680-691
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Tidskriftsartikel (refereegranskat)abstract
- It is demonstrated that in the [La0.67Ca0.33MnO3(d = 9 nm)/La0.67Sr0.33MnO3(9 nm)](3) and [La0.67Ca0.33MnO3(9 nm)/SrTiO3(2 nm)/La0.67Sr0.33MnO3(9 nm)](3) superlattices with the interlayer barriers of nonmagnetic dielectric SrTiO3, the magneto-optical Kerr and magnetorefraction (magnetoreflection and magnetotransmission of unpolarized light) effects have large values close to those for the heterostructures of the same composition. The defects and strain in the layers and at interfaces of superlattices result in appearance of additional band in the Kerr effect spectrum, temperature hysteresis, and abnormal temperature dependence of the Kerr effect. It is shown, that the resonant-like contribution to the magnetoreflection spectra of superlattices is due to the shift of the minima in reflection coefficient near the phonon bands by magnetic field. The increase in magnetotransmission of superlattices relative to a single layered film is due to multiple transmission of light through the layers of superlattices. The intermixing effects at interfaces and deviations of composition of layers from stoichiometry both influence the values of magnetorefraction effect in superlattices and the shapes of their temperature dependences.
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