| 1. |
- Fang, AP, et al.
(författare)
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Theoretical study of electromagnetically induced transparency in Er3+: YAlO3 crystal
- 2003
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Ingår i: Physica B: Condensed Matter. - 0921-4526. ; 328:3-4, s. 204-210
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Tidskriftsartikel (refereegranskat)abstract
- By using the density matrix theory of interaction between light and matter, and relevant parameter calculations of the relaxation rate, the dipole matrix elements and the ion density for a three-level ladder model, we have discussed theoretically the possibility to realize electromagnetically induced transparency (EIT) in Er3+:YA1O(3) crystal. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 2. |
- Gershenson, M. E., et al.
(författare)
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Quantum interference effects in percolated metal networks
- 1994
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Ingår i: Physica B: Condensed Matter. - : Elsevier BV. - 0921-4526. ; , s. 1109-1110
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Konferensbidrag (refereegranskat)abstract
- Quantum corrections (QC) to the resistivity due to weak localization (WL) and electron-electron interaction (EEI) have been measured for percolated metal networks with percolation coherence length z comparable to the quantum length scales-the phase-breaking length L and the thermal diffusion length LT. Far from the percolation metal-insulator transition (MIT) the `macroscopic' disorder is averaged over the quantum lengths (L,LTz) and the QC are of the universal two-dimensional (2D) type with R=R(z), where R(z) is the resistance per square at scales larger than z. A crossover 2D1D in the dimensionality of the QC and the Nyquist phase-braking mechanism is observed near the MIT, where zL,LT
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| 3. |
- Hedin, Lars, et al.
(författare)
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Extrinsic and intrinsic processes in EXAFS
- 1989
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Ingår i: Physica B. - : Elsevier BV. - 0921-4526. ; 158, s. 344-346
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Konferensbidrag (refereegranskat)abstract
- The author extends the ideas of Bardyszewski and Hedin (1987) to treat EXAFS. He summarises the theory, adds new viewpoints and extends the theory.
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| 4. |
- Koblischka, M. R., et al.
(författare)
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Paramagnetic Meissner response of an artificially granular YBCO thin film
- 2000
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Ingår i: Physica B: Condensed Matter. - 0921-4526. ; 284-288, s. 599-600
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Konferensbidrag (refereegranskat)abstract
- Field-cooling measurements on an YBa2Cu3Oy thin film, patterned into a hexagonal close-packed lattice of disks with a diameter of 50 m reveal a paramagnetic Meissner response (PME) when cooled in fields below 1 mT. In contrast to previous investigations on Nb and melt-cast Bi-2212, the PME in this artificial granular film is attributed to field trapping in the space between the disks
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| 5. |
- Lipinska-Kalita, KE, et al.
(författare)
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High-pressure studies of titanium pyrophosphate by Raman scattering and infrared spectroscopy
- 2003
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Ingår i: Physica B: Condensed Matter. - 0921-4526. ; 337:1-4, s. 221-229
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Tidskriftsartikel (refereegranskat)abstract
- High-pressure investigations of titanium pyrophosphate, TiP2O7, in diamond anvil cell have been performed at room temperature using in situ Raman scattering and Fourier transform infrared spectroscopy (FTIR). The endeavor was to acquire information on pressure-induced structural transformations such as phase transitions and amorphization occurring in the crystal lattice. The pressure-stimulated alterations in the spectral profile, the position, and the intensity of the stretching and bending modes Of PO4 tetrahedral structural units have been investigated up to 42.8 and 49.4 GPa for Raman and infrared-active modes, respectively. The spectral changes pointed mostly to the densification and partial amorphization of the crystal lattice. FTIR spectra confirmed that the investigated compound, TiP2O7, compressed smoothly up to the highest investigated pressures. The spectroscopic studies did not indicate an unambiguous structural transformation matching to a pressure-driven phase transition. The reversibility to ambient pressure structure upon decompression was implied by FTIR but was not confirmed by Raman spectroscopy. The mode Gruneisen parameters were calculated for the various Raman and infrared-active vibrational modes. The results obtained are consistent with our previous high-pressure synchrotron radiation-based X-ray diffraction investigations. (C) 2003 Elsevier B.V. All rights reserved.
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| 6. |
- Mortensen, K., et al.
(författare)
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Shear devices for in situ structural studies of block-copolymer melts and solutions
- 1995
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Ingår i: Physica B: Condensed Matter. - : Elsevier BV. - 0921-4526. ; 213, s. 682-684
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Tidskriftsartikel (refereegranskat)abstract
- Structural studies of soft material while exposed in situ to stretch or shear provide a new experimental technique which gives important insight into polymer dynamics. Such devices can be used for making single-domain block-copolymer and colloidal mesophases, and to study various growth mechanisms. In addition, combined structure and shear instruments can give detailed insight into the influence of fluctuations. Two types of shear device, the Couette cell and a parallel plate device, are presented, and some applications are shown.
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| 7. |
- Agren, P., et al.
(författare)
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Hysteretic current-voltage characteristics and Coulomb blockade in 1D-arrays of Josephson junctions
- 2000
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Ingår i: Physica. B, Condensed matter. - 0921-4526 .- 1873-2135. ; 280:04-jan, s. 414-415
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Tidskriftsartikel (refereegranskat)abstract
- The IV characteristics (IVC) of 1D-arrays of small capacitance Josephson junctions with E-C similar to E-J have been measured. The IVC show Coulomb blockade of Cooper pair tunneling and exhibit a pronounced hysteresis which appears to be dual to the well-known resistively shunted junction behavior of ordinary Josephson junctions. A dual serially resistive junction model is used to qualitatively explain the measured data.
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| 8. |
- Andersen, O., et al.
(författare)
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Piezospectroscopic analysis of the hydrogen-carbon complexes in silicon
- 2001
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Ingår i: Physica. B, Condensed matter. - 0921-4526 .- 1873-2135. ; 308, s. 139-142
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Tidskriftsartikel (refereegranskat)abstract
- We have observed the donor (Ec-0.22 eV) and acceptor (Ec-0.16 eV) levels related to hydrogen-carbon complexes in silicon. The donor level is only detected at low temperatures after proton implantation. This hydrogen-carbon complex irreversibly reconfigures at temperatures above 225 K to a configuration characterized by the acceptor level, which is stable up to room temperature. The same acceptor level is also observed after atomic hydrogen diffusion. We have used Laplace transform deep level transient spectroscopy (DLTS) to show the influence of uniaxial stress on the electron emission process and the effect of the stress-induced alignment for the acceptor state. The pattern of the Laplace DLTS peak splittings indicate a trigonal symmetry of the defect. First principles calculations were carried out on the hydrogen-carbon defects with a view of determining their electrical levels and stress response for comparison with the experimental results.
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| 9. |
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| 10. |
- Andersson, K., et al.
(författare)
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Synchronous Cooper pair tunneling in a 1D-array of Josephson junctions
- 2000
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Ingår i: Physica. B, Condensed matter. - 0921-4526 .- 1873-2135. ; 284, s. 1816-1817
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Tidskriftsartikel (refereegranskat)abstract
- We have studied 1D-arrays of Josephson junctions with a gate capacitively coupled to the middle of the array. The SQUID shape of each junction enables tuning of the Josephson coupling energy, El. By adding a signal to the gate with a radio-frequency f we create a step in the I-V characteristics at the value I = 2ef: The step is clearly visible as a peak in the differential resistance dI/dV and can be seen in the whole frequency range studied (10-90 MHz).
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