J. Phys. IV France 07 (1997) C1-303-C1-306
Synthesis, X-Ray, Neutron and Magnetic Studies of New In-Plane Anisotropy M-Hexaferrites BaFe12-2xAxMexO19 (A = Ru, Ir ; Me = Co, Zn)E. Brando1, H. Vincent1 and J. Rodriguez-Carjaval2
1 L.M.G.P., URA 1109 du CNRS, E.N.S. de Physique de Grenoble, 38402 Saint-Martin-d'Hères, France
2 L.L.B., C.E.N. Saclay, 91191 Gif-sur-Yvette, France
Ti-Co substituted M-hexaferrites have been extensively investigated as promising materials for magnetic recording or microwave devices. Doping BaM hexaferrite with Ru-Me or Ir-Me (Me = Zn, Co), compounds are obtained with much higher Tc and Ms values than with Ti-Co elements. Powders and single crystals of BaFe12-2xAxMexO19 have been prepared. Magnetization measurements have been performed on single crystals at room and liquid helium temperatures, and magnetic anisotropy constants K1 and K2 calculated. Precise crystal structures of substituted compounds have been determined by X-ray diffraction, and cation distribution on all crystallographic sites refined. Magnetic structures of (Ru-Co)x and (Ir-Zn)x substituted hexaferrites with x = 0.3 and 0.8 have been determined by using neutron diffraction. According to these studies, magnetic anisotropy change is correlated with the substitution of A for Fe cations on bipyramidal and octahedral sites in the R block, and Me for Fe cations on tetrahedral and bipyramidal sites. Magnetic moments rotate progressively with x from the c-axis to the (a, b) plane.
© EDP Sciences 1997