Dresden 2017 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 41: Micromagnetism / Computational Magnetics
MA 41.8: Vortrag
Mittwoch, 22. März 2017, 17:00–17:15, HSZ 101
Size-induced changes of structural and ferromagnetic properties in La1-xSrSrMnO3 nanoaparticles — •Cornelia Hintze1, Dirk Fuchs1, Michael Merz1,2, Houari Amari3, Christian Kübel2,3, Meng-Jie Huang1, Annie Powell3,4, and Hilbert von Löhneysen1 — 1Karlsruhe Institut für Technologie, Institut für Festkörperphysik, 76021 Karlsruhe — 2Karlsruhe Institut für Technologie, Karlsruhe Nano Micro Facility, 76021 Karlsruhe — 3Karlsruhe Institut für Technologie, Institut für Nanotechnologie, 76021 Karlsruhe — 4Karlsruhe Institut für Technologie, Institut für Anorganische Chemie, 76021 Karlsruhe
La1-xSrxMnO3 nanoparticles (NP) were grown by microemulsion, with Sr concentrations from x=0.35 to 0.50 and diameters between 20 and 40 nm. This technique allows the controlled growth of structurally well-defined NP in a range of sizes using the same preparation conditions. With decreasing particle size, the unit cell volume and the Mn-O bond length increase, while the Mn-O-Mn bond angle decreases. The size-dependent change of structural properties is possibly related to surface effects or disorder. With the decrease of NP size the ferromagnetic ordering temperature TC decreases by up to 20%. The reduction of TC can be understood with respect to structural changes: the increase of Mn-O bond length and decrease of Mn-O-Mn bond angle weaken the double-exchange coupling and hence reduce TC. In addition the intrinsic finite-size effect reduces TC. The observed size-induced change of magnetic properties may allow for a controlled manipulation of magnetism in La1-xSrxMnO3 NP by varying NP size.