Magnetic, Mössbauer, and neutron diffraction investigations of W-type hexaferrite BaZn2−<i>x</i>Co<i>x</i>Fe16O27 single crystals

Abstract

Macroscopic magnetic measurements, Mössbauer, and neutron diffraction studies have been carried out on BaCoxZn2−xFe16O27 [(Zn−Co)2-W] single-crystal hexaferrites. The extrapolated saturation magnetization values σs(0) are slightly lower than those found in the literature. Such differences have been justified as due to the different Co and Zn distributions among the tetrahedral sites.The Co ions induce a strong planar contribution to the magnetic anisotropy. At low temperature, the spin order, found from the macroscopic magnetic measurements and preliminary neutron diffraction studies, is planar, while the Mössbauer data indicate a conical order with an angle of 70° with respect to the c axis. By increasing the temperature, the cobalt anisotropy decreases and a spin reorientation to easy axis is observed.