Strain-driven attenuation of superconductivity in heteroepitaxial perovskite/YBCO/perovskite thin films

H. Zhang; A. Nguyen; T. Gredig; J. Y. T. Wei

paper

Strain-driven attenuation of superconductivity in heteroepitaxial perovskite/YBCO/perovskite thin films

arXiv:1710.10668

Abstract

To distinguish between the effects of strain and magnetism on the superconductivity in $c$ -axis La $_{2/3}$ Ca $_{1/3}$ MnO $_{3}$ /YBa $_{2}$ Cu $_{3}$ O $_{7 - δ}$ (LCMO/YBCO) heterostructures, we study perovskite/YBCO/perovskite thin films using either ferromagnetic LCMO or paramagnetic LaNiO $_{3}$ (LNO) as perovskite. For a lattice-symmetry matched comparison, we also use orthorhombic PrBa $_{2}$ Cu $_{3}$ O $_{7 - δ}$ (PBCO) in place of the pseudocubic perovskites. Unlike PBCO/YBCO/PBCO, both LCMO/YBCO/LCMO and LNO/YBCO/LNO trilayers show strong attenuation of the superconducting $T_{c}$ as YBCO layer thickness is reduced from 21.4 to 5.4 nm. Our results indicate that heteroepitaxial strain, rather than long-range proximity effect, is responsible for the long length scales of $T_{c}$ attenuation observed in $c$ -axis LCMO/YBCO heterostructures.