Dresden 2014 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 107: Poster: Emerging oxide semiconductors / Oxides other than ZnO and its relatives

HL 107.5: Poster

Donnerstag, 3. April 2014, 17:00–20:00, P1

First principles investigation of influence of point defects on the magnetic properties of zinc ferrite — •Waheed A. Adeagbo¹, Sanjeev K. Nayak¹, Martin Hoffmann^1,2, Arthur Ernst^2,3, and Wolfram Hergert¹ — ¹Institute of Physics, Martin Luther University Halle-Wittenberg, Halle, Germany — ²Max Planck Institute of Microstructure Physics, Halle, Germany — ³Wilhelm-Ostwald-Institut für Physikalishe und Theoretishe Chemie, Universität Leipzig, Leipzig, Germany

We investigate the role of point defects (vacancies and impurities) in inducing local ferromagnetic order in ZnFe₂O₄, which is otherwise an antiferromagnetic system. Our studies are performed by the first-principles density functional theory using the VASP package with GGA and GGA+U. Lattice defects such as anion (V_O) and cation (V_Fe, V_Zn) vacancies and vacancy complexes (V_Fe−O, V_Zn−O), substitution of Mg at the tetrahedral Zn site and the interstitial Fe at the empty tetrahedral site are some of the defects under our consideration. In a recent experimental work, by characterization of nanoparticles and thin films of ZnFe₂O₄ samples from XMCD measurements [1], it is deduced that V_O is responsible for enhancement of local ferromagnetic ordering. In a similar line, the influence of other defects on the magnetic properties of both normal and inverse spinel are of interest. The stability of the defects at different experimental growth conditions are estimated by analysis of the defect formation energies at various chemical potentials of the constituting elements in our calculations.
[1] C. E. Rodríguez Torres et al., Phys. Rev. Lett. (2013) (submitted).