NiTi substituted hexaferrites for magnetic recording

In order to obtain hexagonal ferrites with improved characteristics for application in the field of the magnetic recording, the ferrimagnetic Sr(NiTi)/sub x/ Fe/sub 12-2x/O/sub 19/ system is studied. Preliminary investigations suggested that NI is more effective than Co in reducing the magnetic anisotropy of hexaferrites. The system was analyzed as a function of the degree of substitution x and of the reaction temperature T/sub R/ and time tau . The reactivity of the mixtures and their magnetic characteristics ( sigma , H/sub c/, H/sub A/, T/sub c/) were measured, and from the /sub chi T/(H) data it was possible to distinguish between single-domain or polydomain particles. The results are presented. The influence of the extraneous magnetic phases on the coercive field value was also studied and a preliminary investigation of the relation between coercive and anisotropy fields was carried out.<
>