Microwave resonant and zero-field absorption study of pure and doped ferrite nanoparticles

G.V. KURLYANDSKAYA; S.M. BHAGAT; JACOBO, S.E; J. C. APHESTEGUY; N.N. SCHEGOLEVA

JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2011 vol. 72 p. 276 - 285

0022-3697

Microwave  absorption  was  studied  for  magnetic  nanoparticles  of  Fe3O4  (A)  prepared  by  co-precipitation and Ni0.35Cu0.15Zn0.5Fe2O4 and (B) nanoparticles prepared by  the sol-gel combustion method at different temperature. In all cases only one ferromagnetic resonance line was observed which  indicated  that  the materials were magnetically uniform. The  linewidths were  large mainly because  of  the  wide  variations  in  particle  sizes,  shapes  and  orientations.  As  expected,  A  type nanoparticles  showed  no  absorption  at  zero  field.  However,  B  type  nanoparticles  exhibited  a sizable  loss  at  a  zero-field  and  the  effect  increases  with  the  increase  of  reaction  temperature. Mechanical crushing of the sample further enhanced the absorption