Magnetic anisotropy and magnetostriction of LaFe12O19

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...

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Veröffentlicht in:	Journal of magnetism and magnetic materials 2007-03, Vol.310 (2), p.2587-2589
Hauptverfasser:	GROSSINGER, R, KUPFERLING, M, HAAS, M, MÜLLER, H, WIESINGER, G, RITTER, C
Format:	Artikel
Sprache:	eng
Schlagworte:	Condensed matter: electronic structure, electrical, magnetic, and optical properties Exact sciences and technology Magnetic anisotropy Magnetic properties and materials Magnetic resonances and relaxations in condensed matter, mössbauer effect Magnetically ordered materials: other intrinsic properties Magnetomechanical and magnetoelectric effects, magnetostriction Mössbauer effect other γ-ray spectroscopy Physics
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Zusammenfassung:	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 Mossbauer 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.
ISSN:	0304-8853
DOI:	10.1016/j.jmmm.2006.11.002