Physicist at CNRS-Thales Lab, France
Our work on periodic vortex pinning in high-temperature superconducting films with ordered nanostructures of a half-metallic manganite has been recently published in Nano Letters (a free access version can be found in cond-mat).
This work is done in collaboration with the group of Prof. Jacobo Santamaria (GFMC, University Complutense of Madrid).
The design of artificial vortex pinning landscapes is a major goal towards large scale applications of cuprate superconductors. While disordered nanometric inclusions have been explored so far to produce enhancements of the critical current, the effect of ordered oxide nanostructures remains essentially unexplored. This is due to the very small nanostructure size imposed by the short coherence length, and to the technological difficulties in the nanofabrication process.
Here we show that the unusual long range suppression of the superconductivity occurring at the interface between manganites and cuprates affects vortex nucleation and provides a novel vortex pinning mechanism. In particular, we show evidence of commensurate pinning in YBCO films with ordered arrays of LCMO ferromagnetic nanodots. Vortex pinning results from the proximity induced reduction of the condensation energy at the vicinity of the magnetic nanodots, and yields an enhanced friction between the nanodot array and the moving vortex lattice in the liquid phase.
This result proves all-oxide ordered nanostructures a powerful route for the artificial manipulation of vortex matter in cuprates, complementary to the masked ion irradiation and ferroelectric field-effet induced pinning we demonstrated earlier.