Physics – Condensed Matter – Superconductivity
Scientific paper
2000-01-05
Physics
Condensed Matter
Superconductivity
10 pages, 4 figures
Scientific paper
We report the observation of a weak spontaneous magnetic field appearing at the transition temperature of $\rm YBa_2Cu_3O_{7-\delta}$ into the superconducting state. The effect is observed in 14 out of 15 epitaxial films grown on different substrates and by two distinct techniques. The average magnetic field sensed by the SQUID magnetometer is of the order of 10$^{-5}$ G. The effect indicates a breaking of both parity and time reversal symmetries in the superconductor. We consider two different interpretations: (i) The condensate carries an intrinsic magnetic moment. At T=0, this moment is between $\rm 10^{-2} \mu_B$ and $\rm 10^{-4} \mu_B$ per plaquette, depending whether the width of the unscreened region near the edge of the film is the coherence length or the penetration length. (ii) $\pi$ junctions which may exist near the edges produce circulating supercurrents and magnetic flux. Constraints imposed on these scenarios by temperature and geometry dependence of the data are discussed.
Auerbach Assa
Carmi Raz
Koren Gad
Polturak Emil
No associations
LandOfFree
Appearance of spontaneous macroscopic magnetization at the superconducting transition of YBCO does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Appearance of spontaneous macroscopic magnetization at the superconducting transition of YBCO, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Appearance of spontaneous macroscopic magnetization at the superconducting transition of YBCO will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-90228