Ferromagnetic/Superconducting All Oxide Superlattices and Heterostructures | ||
| Egyptian Journal of Solids | ||
| Article 1, Volume 26, Issue 1, 2003, Pages 1-13 PDF (480.92 K) | ||
| DOI: 10.21608/ejs.2003.150007 | ||
| Abstract | ||
| The physical properties of the perovskite-type oxide RuSr2GdCu2O8 have been recently discussed in the view of a simultaneous occurrence of superconductivity and ferromagnetism. In order to explore some peculiarities of these compounds we have prepared superlattices of oxides that are known to be either ferromagnetic (La.67Ca.33MnO3) or superconducting (YBa2Cu3O7). These superlattices serve as model systems to understanding the physics of RuSr2GdCu2O8. The YBCO/LCMO superlattices have been grown by pulsed laser deposition with individual layer thickness ranging from 4 to 200 unit cells for the YBa2Cu3O7 and 10 to 500 unit cells for the La.67Ca.33MnO3. Measuring dc-transport and magnetic properties some novel effects have been found due to a coupling between the layers observed in the superlattices. Superlattices with individual thickness of the constituent materials of 4 nm e.g. show a reduced Curie temperature of 120K and a superconducting transition temperature of 52K. Lowering the temperature of reentrant normal state occurs at T = 25K. Switching off the electronic interlayer coupling by the introduction of insulating SrTiO3 spacer layers leads to the intrinsic critical temperatures. For the explanation of the results several novel concepts have to be developed based on a long range ferromagnetic interlayer coupling and a novel long range superconducting proximity effect. | ||
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