Growth and characterization of La0.67Sr0.33MnO3/YBa2Cu3O7−δ bilayers

Jacob J Wisser,Yuri Suzuki

doi:10.1063/9.0000105

Abstract

Understanding the interplay of ferromagnets and superconductors requires high quality interfaces. To this end, we have fabricated heterostructures of the cuprate superconductor YBa2Cu3O7−δ (YBCO) with the metallic ferromagnet La0.67Sr0.33MnO3 (LSMO) via pulsed laser deposition on SrTiO3 (STO) (001) and (LaAlO3)0.3(Sr2TaAlO6)0.7 (LSAT) (001) substrates. By varying the YBCO thickness from 1.7-13.6 nm while keeping the LSMO thickness at 12 nm, we have studied the interplay between ferromagnetism and superconductivity in the in-plane transport and magnetic properties of the bilayers. X-ray reflectivity data indicate the presence of a 2-3 nm thick interfacial layer between the LSMO and YBCO layers in all heterostructures. In-plane transport measurements exhibit suppression of the superconducting transition temperature from bulk YBCO values. Magnetometry measurements indicate high LSMO saturation magnetization values for samples grown on STO substrates and even higher (bulk-like) magnetization for bilayers grown on LSAT substrates. Together these results indicate that the interdiffused layer is largely attributed to a modified YBCO layer.

Highlights

X-ray diffraction (XRD) results show that we are able to obtain crystalline, epitaxial growth of both LSMO and YBCO, with a minimum YBCO thickness of 8.5 nm required to observe signatures of the (002) Bragg reflection
We note that the position of the YBCO (002) peak does not change with increasing thickness when tYBCO > 10.2 nm, suggesting that the strain state of the YBCO does not change in this thickness range
We note that the Tc monotonically increases with increasing YBCO thickness, with a minimum thickness of tYBCO = 5.1 nm for superconductivity

Summary

Introduction

X-ray diffraction (XRD) results show that we are able to obtain crystalline, epitaxial growth of both LSMO and YBCO, with a minimum YBCO thickness of 8.5 nm required to observe signatures of the (002) Bragg reflection. In-plane transport measurements in the van der Pauw configuration for bilayers grown on STO (001) substrates (Figure 2) reflect the electronic properties of the YBCO and LSMO layers.

Results

Conclusion