Anisotropy of local and hyperfine magnetic fields in 57Fe nuclei in the hexaferrite SrFe12O19

Local magnetic fields and their anisotropy in Fe-57 nuclei are measured in the domain boundaries for the sites 4f(1) of Fe3+ ions of the hexaferrite SrFe12O19 in the temperature range 4.2-295 K. The anisotropy of the magnetic moment moduli of Fe3+ ions is determined at low temperatures. The anisotropy of the magnetic moment moduli is considered as the physical factor responsible for the hyperfine field anisotropy. The connection between the anisotropy of magnetic moment moduli and the magnetic characteristics of the ferrite is considered in the molecular field approximation. (C) 1998 American Institute of Physics. [S1063-777X(98)00708-7].