The influence of Nd-Co substitution on non-stoichiometric strontium hexaferrite nanoparticles

P. G. BERCOFF; C. HERME; S. E. JACOBO

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

Elsevier

Año: 2009 vol. 321 p. 2245 - 2250

0304-8853

Non-stoichiometric Nd-Co substituted hexaferrites of composition Sr(1-x) Ndx Fe12(1-x) Cox O19 (x= 0 to 0.4) were prepared by the self-propagating combustion method and subsequent heat treatments. Structural characterization of the samples showed that the M-type hexagonal structure can be maintained for substitutions x<0.4 without segregation of secondary phases on samples calcined at 1100ºC. The crystallites sizes range between 50 and 70 nm. Mössbauer spectroscopy results indicate that the iron vacancies are not evenly distributed over the lattice and that Co/Fe substitution mainly takes place in site 4f2. Magnetic measurements reveal that the values of saturation magnetization MS increased from 72 to 76 emu/g (x=0-0.2) while coercivity Hc increased from 2100 to 4670 Oe (x=0-0.3). Nd-Co substitutions enhance magnetic properties in deficient iron Sr hexaferrites.