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.
|Titolo:||Thermodynamic nature of the 0 − π quantum transition in superconductor/ ferromagnet/ superconductor trilayers|
|Data di pubblicazione:||2014|
|Citazione:||Thermodynamic nature of the 0 − π quantum transition in superconductor/ ferromagnet/ superconductor trilayers / Pompeo N.; TOROKHTII K; Cirillo C.; Samokhvalov A. V.; Ilyina E. A.; Attanasio C.; Buzdin A. I.; Silva E.. - In: PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS. - ISSN 1098-0121. - 90:6(2014), p. 064510.064510.|
|Appare nelle tipologie:||1.1 Articolo in rivista|