Magnetostriction and magnetisation of CeFe2

Magnetostriction and magnetisation measurements are made on a polycrystalline sample of the cubic Laves phase compound CeFe2 in pulsed magnetic fields up to 18 T and over the temperature range 5 to 300 K. A sharp increase in magnetostriction is observed at fields of about 3 T and at temperatures below 150 K. The magnitude of the first-order change in strain increases with decreasing temperature and at 5 K it amounts to approximately 150 × 10−6 which is a 200% increase in the parallel magnetostriction. The critical field for the transition decreases slowly with decreasing temperature. The corresponding change in magnetisation is of the order of 8% at 5 K. It is proposed that this transition corresponds to a first-order rotation of the magnetisation vector due to a particular combination of anisotropy constants. In particular, the effect of the eighth-order constant K3 which also leads to a non-symmetry easy direction above 150 K, is likely to be important.