Crystallographic and magnetic properties of Cu2X, Co2X, and Ni2X hexaferrites

Abstract

We have investigated the synthesis conditions and the magnetic properties of X-type hexagonal ferrites. It is found that Ba2Cu2Fe28O46 (Cu2X), Ba2Co2Fe28O46 (Co2X), and Ba2Ni2Fe28O46 (Ni2X) ferrites can be synthesized at a sintering temperature of 1250 °C. The x-ray diffraction patterns for Cu2X, Co2X, and Ni2X samples are in good agreement with the pattern calculated from the atomic coordinates for Ba2Fe30O46 (Fe2X), where two diffraction peaks at Q=2.24 and 2.30 Å−1 are clearly observed in contrast with other M-, W-, Y-, and Z-types hexagonal ferrites. It is also found that the low-temperature spontaneous magnetizations of Cu2X, Co2X, and Ni2X ferrites are 47.5 μB/f.u., 43.4 μB/f.u., and 43.2 μB/f.u., respectively. The cation distributions for Cu2X, Co2X, and Ni2X are discussed within the model of a Néel-type collinear ferrimagnetic structure.