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MA: Fachverband Magnetismus

MA 39: Magnetic Particles

MA 39.10: Vortrag

Donnerstag, 10. März 2016, 12:00–12:15, H31

SmCo nanoparticles from the gas-phase: On the stability of intermetallic SmCo₅ at the nanoscale. — •Frank Schmidt^{1, 2}, Ludwig Schultz¹, and Bernd Rellinghaus¹ — ¹IFW Dresden, Helmholtzstraße 20, D-01069 Dresden, Germany — ²TU Dresden, IFWW, D- 01062 Dresden, Germany

SmCo₅ is among the magnetic materials with the highest magneto-crystalline anisotropies and Curie temperatures, T_C, respectively. The latter are indispensable for high temperature applications, where Nd₂Fe₁₄B can no longer be used. In the present study, we investigate the formation and phase stability of SmCo nanoparticles from the gas phase, which could serve as a model system for their (nanostructured) bulk counterparts. Particular attention is paid to the question, if the intermetallic phase SmCo₅ (or one of its derivates) forms in particles with only a few nanometer in size, which grow without contact to any solid or liquid matrix in a low pressure Ar atmosphere. This question is closely related to the possible occurrence of segregation that is frequently observed in nanoscale materials and that goes along with a deterioration of the magnetic properties. Aberration-corrected transmission electron microscopy is used in combination with spectroscopic methods to determine the local structure and the chemical composition. It is found that, depending on the phase formation temperature, SmCo nanoparticles tend to de-mix. The magnetic properties of the particle ensembles, as determined from VSM measurements, are correlated with the predominant core-shell structure of the SmCo particles.