Magnetic properties of Zn- and Ti-substituted barium hexaferrite

We have studied the magnetic properties of the barium hexaferrite series Ba Fe12-2xZnxTixO19 for 0 less than or equal to x less than or equal to 2.0, b y means of magnetization (SQUID), neutron diffraction and Mossbauer measure ments. For x less than or equal to 0.8 we observe an increase of the low-te mperature net magnetization relatively to the unsubstituted sample. For lar ger substitution, our studies indicate a deviation of the Fe spins from the collinear structure which leads to a decrease of the net magnetization. We have investigated to what extent and accuracy the molecular field approxim ation describes the observed magnetic properties for the x = 0 and 0.4 samp les taking into account the exchange integrals between different magnetic s ublattices. (C) 1999 Elsevier Science B.V. All rights reserved.