Thermodynamic nature of the 0-π quantum transition in superconductor/ferromagnet/superconductor trilayers
SAMOKHVALOV, A. V.
Institute for Physics of Microstructures of the RAS
Lobachevsky State University of Nizhny Novgorod
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Institute for Physics of Microstructures of the RAS
Lobachevsky State University of Nizhny Novgorod
Langue
en
Article de revue
Ce document a été publié dans
Physical Review B: Condensed Matter and Materials Physics (1998-2015). 2014-08-21, vol. 90, n° 6, p. 064510 (1-7)
American Physical Society
Résumé en anglais
In structures made up of alternating superconducting and ferromagnet layers (S/F/S heterostructures), it is known that the macroscopic quantum wave function of the ground state changes its phase difference across the F ...Lire la suite >
In structures made up of alternating superconducting and ferromagnet layers (S/F/S heterostructures), it is known that the macroscopic quantum wave function of the ground state changes its phase difference across the F layer from 0 to π under certain temperature and geometrical conditions, hence the name "0-π" for this crossover. We present here a joint experimental and theoretical demonstration that 0-π is a true thermodynamic phase transition. Microwave measurements of the temperature dependence of the London penetration depth in Nb/Pd0.84Ni0.16/Nb trilayers reveal a sudden, unusual decrease of the density of the superconducting condensate (square modulus of the macroscopic quantum wave function) with decreasing temperature, which is predicted by the theory here developed as a transition from the 0 state to the π state. Our result for the jump of the amplitude of the order parameter is a thermodynamic manifestation of such a temperature-driven quantum transition.< Réduire
Mots clés en anglais
Multilayers
superlattices
Magnetic properties including vortex structures and related phenomena
Proximity effects
Andreev reflection
SN and SNS junctions
Surface impedance
heterostructures
Project ANR
Etats de Majorana et d'Andreev dans des circuits hybrides combinant des matériaux magnétiques et supraconducteurs - ANR-12-BS04-0016
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