Studies on the relation between the magnetic properties and positron lifetime of ALNICO 8 permanent magnet alloys

The present paper has studies the relation between the maximum magnetic energy product (MMEP) of columnar crystallizated AlNiCo 8 permanent magnet alloys cooled continuously in magnetic fields and positron lifetime in this material. The experimental results show that the minimum decay constant τ1 reaches gradually its saturation as MMEP increase, this means the trapped effect obviously happens in the specimens with low MMEP. With the increase of MMEP, the τ2 component reflecting the crystal imperfection decreased, hence, the crystal perfection improved. Moessbauer spectroscopic results also show that with the increase of MMEP, the more parts of magnetic moments orientate to magnetizate direction. This work gives valuable data to improve the properties of materials. (author)