Dresden 2011 – wissenschaftliches Programm

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SKM-SYDT: SKM-Symposium Diffusionless Transformations in Magnetic and Ferroelectric Bulk and Thin Films

SKM-SYDT 1: Diffusionless Transformations in Magnetic and Ferroelectric Bulk and Thin Films

SKM-SYDT 1.5: Hauptvortrag

Donnerstag, 17. März 2011, 12:30–13:00, TRE Ma

Orthorhombic to tetragonal transition of SrRuO₃ layers in Pr_0.7Ca_0.3MnO₃/SrRuO₃ superlattices — •Michael Ziese¹, Francis Bern¹, Ionela Vrejoiu², Eckhard Pippel², and Elizaveta Nikulina² — ¹Div. of Superconductivity and Magnetism, University of Leipzig, D-04103 Leipzig, Germany — ²Max Planck Institute of Microstructure Physics, D-06120 Halle, Germany

In perovskite superlattices (SLs) the intimate interplay between structural, magnetic and electronic properties can be modified by geometrical constraints. This is explored in this work by the study of the crystallographic, magnetic and magnetotransport properties of ultrathin SrRuO₃ (SRO) layers embedded in SLs. Pr_0.7Ca_0.3MnO₃/SrRuO₃ (PCMO/SRO) SLs were grown by pulsed laser deposition on vicinal SrTiO₃ substrates with a miscut angle of about 0.1^∘, uniform TiO₂-termination and an atomically flat terrace morphology. The SRO layer thickness was kept constant at 4 nm, whereas the PCMO layer thickness was varied between 1.5 and 4 nm. High resolution TEM investigations of the PCMO/SRO SLs showed that the PCMO layers were orthorhombic throughout, whereas the SRO layers were orthorhombic when adjacent to 1.5 nm thick PCMO layers and transformed to tetragonal when adjacent to 4 nm thick PCMO layers. This structural transformation profoundly changed the form of the angular dependent magnetoresistance (MR) as well as the direction of the magnetic easy axes. Further the antiferromagnetic interlayer exchange coupling between PCMO and SRO layers was stronger in the orthorhombic than in the tetragonal phase.