Granular superconductivity and charge/orbital order in YBa2Cu3O7/manganite trilayers

Abstract

We studied how the electronic, superconducting, and magnetic properties of YBa2Cu3O7/Nd1-x(Ca1-ySry)xMnO3 multilayers depend on the tolerance factor and the hole doping of the manganite. In particular, we investigated the granular superconducting state and the related magnetic-field-driven insulator-to-superconductor transition that was previously discovered in corresponding multilayers with Pr0.5La0.2Ca0.3MnO3 [B. P. P. Mallett, Phys. Rev. B 94, 180503(R) (2016)10.1103/PhysRevB.94.180503]. We found that this granular superconducting state occurs only when the manganite layer is in a charge/orbital ordered and CE-type antiferromagnetic state (Mn-CO/OO). The coupling mechanism underlying this intriguing proximity effect seems to involve the domain boundaries of the Mn-CO/OO and/or the charge disordered regions of the manganite layer that become more numerous as the hole doping is reduced below x=0.5.