Enhanced Spin Tunneling in a Molecular Magnet Mixed with a Superconductor

arXiv:1509.07291v1
We report characterization and magnetic studies of mixtures of micrometer-size ribbons of Mn12 acetate and micrometer-size particles of YBaCuO superconductor. Extremely narrow zero-field spin-tunneling resonance has been observed in the mixtures, pointing to the absence of the inhomogeneous dipolar broadening. It is attributed to the screening of the internal magnetic fields in the magnetic particles by Meissner currents flowing between superconducting grains surrounding the particles.
The work at the University of Barcelona has been supported by the Spanish Government Project No. MAT2011-23698. A.G.-S. acknowledges support from Universitat de Barcelona. I.I. and J.E. thank the MINECO for the Ramon y Cajal contract and the FPI fellowship, respectively. The work of EMC at CUNY Lehman College has been supported by the Office of Science of the U.S. Department of Energy through grant No. DE-FG02-93ER45487.