Magnetoresistance at artificial interfaces in the itinerant SrRnO3 ferromagnet

The magnetoresistance across interfaces in the itinerant ferromagnetic oxid e SrRuO3 have been studied. To define appropriately the interfaces, epitaxi al thin films have been grown on bicrystalline and laser-patterned SrTiO3 s ubstrates. Comparison is made with results obtained on similar experiments using the double-exchange ferromagnetic oxide La2/3Sr1/3MnO3. It is found t hat in SrRuO3, interfaces induce a substantial negative magnetoresistance, although no traces of the low-field spin tunneling magnetoresistance are fo und. We discuss these results on the basis of the distinct degree of Spin p olarization in ruthenates and manganites and the different nature of the su rface magnetic layer formed at interfaces.