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MA: Fachverband Magnetismus

MA 49: POSTER II

MA 49.33: Poster

Donnerstag, 19. März 2015, 15:00–18:00, Poster A

Influence of oxygen vacancies on the magnetic properties of ZnFe2O4 — •Karen L. Salcedo Rodríguez1, Martin Hoffmann2,3, Jhon J. Melo Quintero1, Gustavo Pasquevich1, Pedro Mendoza Zelis1, Leonardo A. Errico1, Silvana J. Stewart1, Wolfram Hergert2, and Claudia E. Rodríguez Torres11National University of La Plata, Argentina — 2Martin Luther University Halle-Wittenberg, Germany — 3Max Planck Institute for Microstructure Physics, Halle, Germany

We continue our experimental and theoretical study on bulk ZnFe2O4 (ZFO) powders [1]. ZFO samples were annealed in vacuum up to 600C to control and increase the number of oxygen vacancies. The x-ray diffraction patterns indicate that all samples consist of single-phase ferrite. However, the magnetic measurements show the coexistence of ferromagnetic-like and paramagnetic components. For the saturation magnetization, the paramagnetic susceptibility and the Mössbauer spectroscopy, we observed a qualitative difference for samples which were annealed at temperatures either below or above 400C.

Furthermore, we studied with ab initio calculations ZFO in the normal/inverted spinel structure and in the oxygen-deficient regime. The comparison between the experimental and calculated hyperfine parameters indicated a reduction of inversion by increasing the annealing temperature up to 400C. For higher temperatures, we attributed the oxygen vacancies formation for the observed increase in the saturation magnetization and paramagnetic susceptibility.

[1] PRB 89, 104411 (2014)

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DPG-Physik > DPG-Verhandlungen > 2015 > Berlin