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Author Betouras, J.J.; Ivanov, V.A.; Peeters, F.M.
Title Ginzburg-Landau theory and effects of pressure on a two-band superconductor : application to MgB2 Type A1 Journal article
Year 2003 Publication European physical journal : B : condensed matter and complex systems Abbreviated Journal Eur Phys J B
Volume 31 Issue 3 Pages 349-354
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (up) We present a model of pressure effects of a two-band superconductor based on a Ginzburg-Landau free energy with two order parameters. The parameters of the theory are pressure as well as temperature dependent. New pressure effects emerge as a result of the competition between the two bands. The theory then is applied to MgB2. We identify two possible scenaria regarding the fate of the two Q subbands under pressure, depending on whether or not both subbands are above the Fermi energy at ambient pressure. The splitting of the two subbands is probably caused by the E-2g, distortion. If only one subband is above the Fermi energy at ambient pressure (scenario I), application of pressure diminishes the splitting and it is possible that the lower subband participates in the superconductivity. The corresponding crossover pressure and Gruneisen parameter are estimated. In the second scenario both bands start above the Fermi energy and they move below it, either by pressure or via the substitution of Mg by Al. In both scenaria, the possibility of electronical topological transition is emphasized. Experimental signatures of both scenaria are presented and existing experiments are discussed in the light of the different physical pictures.
Address
Corporate Author Thesis
Publisher Place of Publication Berlin Editor
Language Wos 000181614300008 Publication Date 2004-03-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1434-6028;1434-6036; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.461 Times cited 10 Open Access
Notes Approved Most recent IF: 1.461; 2003 IF: 1.457
Call Number UA @ lucian @ c:irua:94859 Serial 1343
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Author Ball, J.M.; Schryvers, D.
Title The analysis of macrotwins in NiAl martensite Type A1 Journal article
Year 2003 Publication Journal de physique: 4 T2 – 10th International Conference on Martensitic Transformations, JUN 10-14, 2002, ESPOO, FINLAND Abbreviated Journal J Phys Iv
Volume 112 Issue Part 1 Pages 159-162
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) We present a theoretical study of macrotwins arising in cubic to tetragonal martensitic transformations. The results help to explain some features of such macrotwins observed in Ni65Al35.
Address
Corporate Author Thesis
Publisher Place of Publication Les Ulis Editor
Language Wos 000186503200024 Publication Date 2008-08-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1155-4339; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 11 Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:103275 Serial 3569
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Author Ivanov, V.A.; Krstajic, P.M.; Peeters, F.M.; Fleurov, V.; Kikoin, K.
Title On the ferromagnetic exchange in Mn-doped III-V semiconductors Type A1 Journal article
Year 2003 Publication Physica: B : condensed matter T2 – 23rd International Conference on Low Temperature Physics (LT23), AUG 20-27, 2002, HIROSHIMA, JAPAN Abbreviated Journal Physica B
Volume 329 Issue Part 2 Pages 1282-1283
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract (up) We propose a microscopic model for double exchange in GaAs:Mn, GaP:Mn which is based on the interaction between the transition metal impurities and the heavy holes of host semiconductor. The kinematic exchange is derived and the Curie temperature is calculated which agrees with recent experiments. (C) 2003 Elsevier Science B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000183802700400 Publication Date 2003-02-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0921-4526; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.386 Times cited 5 Open Access
Notes Approved Most recent IF: 1.386; 2003 IF: 0.908
Call Number UA @ lucian @ c:irua:103813 Serial 2435
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Author Musolino, N.; Bals, S.; Van Tendeloo, G.; Clayton, N.; Walker, E.; Flükiger, R.
Title Modulation-free phase in heavily Pb-doped (Bi,Pb)2212 crystals Type A1 Journal article
Year 2003 Publication Physica: C : superconductivity Abbreviated Journal Physica C
Volume 399 Issue 1/2 Pages 1-7
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) We report the complete disappearance of the structural modulation in heavily lead-doped Bi2-xPbxSr2CaCu2O8+delta crystals observed by transmission electron microscopy. Crystals with a nominal lead content of x = 0.8, corresponding to an effective lead content of x = 0.39, yield the non-modulated phase. The superconducting properties of this modulation-free phase (beta phase) have been studied and compared to those of undoped crystals displaying the modulated phase (alpha phase). Magnetisation measurements reveal that the irreversibility field H-irr(T) and relaxation rates are strongly improved within the beta phase. Measurements of the lower critical field, H-c1, show that the anisotropy factor, epsilon, is considerably reduced in the modulation-free crystals. This is the signature of stronger coupling between CuO2 layers which in turn deeply influences the effectiveness of the pinning. These measurements explain the enhanced pinning properties in moderately Pb-doped crystals in which the alpha phase and beta phase coexist. The enhanced pinning is not only due to the alpha/beta interfaces, which act as effective pinning centers: the emergence of modulation-free domains, characterized by a strongly reduced anisotropy, also significantly contribute to this effect. (C) 2003 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000186526200001 Publication Date 2003-09-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0921-4534; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.404 Times cited 31 Open Access
Notes Approved Most recent IF: 1.404; 2003 IF: 1.192
Call Number UA @ lucian @ c:irua:54797 Serial 2167
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