Interplay of superconductivity and ferromagnetism in YBa₂Cu₃O₇/ La_1−xSr_xMnO₃ heterostructures

Abstract

Oxide manganite/cuprate superlattices are an attractive model system to study the proximity effect in oxide ferromagnet/cuprate superlattices. This report describes recent experimental results obtained on manganite/cuprate heterostructures. The experimental results are discussed in terms of the impact of hole charge transfer from cuprate to manganite layers on the proximity between the oxide ferromagnet and oxide superconductor layers.

Superconductivity and Magnetism in Nd0.5Sr0.5MnO3/YBa2Cu3O7Superlattices

“…A similar behavior has been observed in other NSMO/YBCO superlattices [5]. This is in contrast to the measurements on LSMO/YBCO superlattices [6], where the transition to superconducting state is observed for the samples with at last 2 unit cell thick YBCO layers. The zero net magnetic moment is observed for a single NSMO film on NdGaO 3 substrate as shown in Fig.…”

“…Measurements of M (H) of NSMO/YBCO superlattices on LSAT substrates in FC mode (not shown) demonstrate a shift of the hysteresis loop along H axis (exchange bias). Such behavior suggests the charge transfer of holes from YBCO layers to NSMO layers similar to the observation on LSMO/YBCO superlattices [6].…”

Magneto-Optics of Spontaneous and Field Induced Vortices in Twinned YBa2Cu3O7-δ/La1-xSrxMnO3Bilayers

“…All the bilayers here presented were grown on twinned single crystals of LaAlO 3 , by multi-target high-pressure dc sputtering from the corresponding sto-ichiometric targets [12,13]. The manganite layers of LSMO, with doping levels x = 0.33 and x = 0.115, are 100 nm thick and on top of them a 50 nm thick YBCO film was grown.…”

Magnetism and superconductivity in oxide ferromagnet/superconductor heterostructures

“…Tunnelling magnetoconductance measurements [24] (TMC) measured for the LSMO(110nm)/ YBCO(8.4nm)/LSMO(110nm) trilayer structure demonstrate a variation of conductivity when magnetic moments in two LSMO layers change the orientation from parallel to antiparallel in the presence of external magnetic field. The observation of switching field, and the TMC measurements in LSMO/YBCO/LSMO trilayer structures may be interpreted as a signature of indirect exchange coupling between ferromagnetic LSMO layers across superconducting YBCO layer, similar as it is observed in GMR systems such as Fe/Cr/Fe trilayers [25].…”