Site preference for Co/sup 2+/ and Ti/sup 4+/ in Co-Ti substituted barium ferrite

Abstract

Co/sup 2+/ and Ti/sup 4+/ substituted M-type barium ferrite, BaFe/sub 12-2x/Co/sub x/Ti/sub x/O/sub 19/, with x from 0 to 0.9 has been prepared using a modified ceramic method and investigated by electron microscopy, vibrating sample magnetometry and Mossbauer spectroscopy. Results show that Co/sup 2+/ and Ti/sup 4+/ cations prefer to occupy the 4f/sub VI/ and 2b crystallographic sites, with 4f/sub IV/ and 2a sites are only slightly involved as well for x>0.6. These site preferences will significantly weaken the uniaxial anisotropy of this material which is attributed to the contribution of iron ions at the 2b and 4f/sub VI/ sites. As a consequence, the coercive force of BaFe/sub 12-2x/Co/sub x/Ti/sub x/O/sub 19/ drastically decreases and the magnetization remains almost a constant as x increases.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>