[Zurück]

R. Grössinger, M. Küpferling, M. Haas, H. Müller, G. Wiesinger, C. Ritter:
"Magnetic anisotropy and magnetostriction of LaFe₁₂O₁₉";
Journal of Magnetism and Magnetic Materials, 310 (2007), 2 Part III; S. 2587 - 2589.

Magnetic anisotropy and magnetostriction of LaFe₁₂O₁₉

R. Grössinger a , M. Küpferling a, M. Haas a, H. Müller a, G. Wiesinger a, C. Ritter b
a Institute for Solid State Physics, Technical University of Vienna; Wiedner Hauptstr. 8-10, Austria
b Institute Laue-Langevin, F-38042 Grenoble, France

Abstract

The temperature dependence of the anisotropy field of LaFe₁₂O₁₉ was measured from 4.2K up to the Curie temperature. Below 110K LaFe₁₂O₁₉ exhibits a structural change from the hexagonal to an orthorhombic structure with spacegroup Cmcm. The origin is related to a change of valence at the 2a site from Fe³⁺ to Fe²⁺ in order to achieve charge compensation, since La³⁺ replaces Sr²⁺ in this material.
This becomes visible in the isomer shift as detected with ⁵⁷Fe Mössbauer spectroscopy at the Fe 2a site. In addition an anomalous
behaviour of the hyperfine field was observed, indicating the presence of an unquenched orbital momentum. This explains the strong
increase of the anisotropy field at low temperatures and the high values of the magnetostriction constant, observed in the experiment.

Ferrites; Anisotropy; Magnetostriction; Mossbauer; Spectroscopy

http://dx.doi.org/10.1016/j.jmmm.2006.11.002