INVESTIGATION OF THERMOMAGNETIC EFFECTS IN MONOCRYSTALLINE COBALT NEAR THE MARTENSITIC PHASE-TRANSITION

The initial susceptibility and the magnetic after-effect (MAE) of [0001]-oriented, prismatic cobalt single crystals are investigated in the temperature range 100 K < T < 800 K using ac techniques. The amplitudes of both the susceptibility and the MAE are characteristically influenced by the temperature-dependent Variations of the crystal anisotropy constants, K-1 and K-2, and by magnetostrictive interactions with dislocations and point defects. It is shown that the concentration of these intrinsic defects may be increased considerably by continued annealing in the vicinity of the allotropic alpha --> beta phase transformation.