d-wave Andreev reflection study of the ab-plane proximity effect in cuprate/manganite and cuprate/nickelate thin films
Abstract
An anomalously long-range proximity effect was previously reported in c-axis thin-film heterostructures of ferromagnetic La2/3Ca1/3MnO3 (LCMO) and superconducting YBa2Cu3O7-δ (YBCO), and attributed to spin-triplet d-wave pairing. However, there is debate over the existence of such long-range proximity effect, given the short c-axis coherence length of YBCO, and since scanning tunneling spectroscopy (STS) on c-axis LCMO/YBCO bilayers has failed to observe any direct evidence. For YBCO/LCMO bilayers oriented along the a-axis, similar STS measurements have reportedly observed a proximity length scale of 30 nm. In this work, we extend these prior STS studies to YBCO/LCMO bilayers oriented along the <110 > axis, a geometry that is expected produce the most robust d-wave Andreev resonance states. We also measure <110 >-oriented LaNiO3/YBCO bilayers, as a non-magnetic control. Our data are analyzed in terms of the overlayer thickness, in an effort to determine the actual length scale of the manganite/cuprate proximity effect in the ab-plane.
This work was supported by NSERC, CFI, OIT, and CIFAR.- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- 2019
- Bibcode:
- 2019APS..MARL08010C