2005/01/19 by M. L. Della Rocca, Maria Luisa Della Rocca, M. Aprili +6 · 1 citation
Mathematics · Physics and Astronomy · #Condensed matter physics #Ferromagnetism #Ising model #Josephson effect #Magnetic properties of thin films #Materials science #Mathematics #Physics #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Randomness #Statistics #Superconductivity #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevlett.94.197003
4 pages, 4 figures
arxiv created 2005/01/19 · openalex publication_date 2005/05/17 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The ground state of highly damped PdNi based 0-pi ferromagnetic Josephson junctions shows a spontaneous half quantum vortex, sustained by a supercurrent of undetermined sign. This supercurrent flows in the electrode of a Josephson junction used as a detector and produces a phi(0)/4 shift in its magnetic diffraction pattern. We have measured the statistics of the positive or the negative sign shift occurring at the superconducting transition of such a junction. The randomness of the shift sign, the reproducibility of its magnitude, and the possibility of achieving exact flux compensation upon field cooling are the features which show that 0-pi junctions behave as classical spins, just as magnetic nanoparticles with uniaxial anisotropy.