Effect of spacer layer thickness on magnetic and electrical properties of La{sub}0.7Sr{sub}0.3 MnO{sub}3/SrTiO{sub}3 superlattices

摘要

The effects of spacer layer (SrTiO{sub}3) thickness on the magnetic and electrical properties of La{sub}0.7Sr{sub}0.3MnO{sub}3/SrTiO{sub}3 superlattices has been studied by fabricating a series of multi- layers on SrTiO{sub}3 (100) substrates by pulsed laser deposition. High quality of the films was ensured by X-ray diffraction and transmission electron microscopy. All studied films are ferromagnetic below a transition temperature Tc. The T0 as well as saturation magnetization Ms depend on the thickness of SrTiO{sub}3. However these dependences are nonmonotonic. The electrical resistivity is metallic-like below 300 K. The magnetoresistance measured at 20 K has been found to depend on the SrTiO{sub}3 thickness and correlates with the magnetic measurements. The results are discussed in terms of surface corrugation due to epitaxial strain, surface dead-layer concept, and interlayer coupling.