MAGNETO-ELASTIC INTERACTIONS IN GADOLINIUM

The effect of the change in easy direction of magnetization on the elastic constants c33 and c44 has been measured in single-crystal gadolinium by means of a pulse-echo technique. One of the constants c33 exhibited a sharp decrease of about 2% over the temperature range -37 to -51°C after which it slowly returned to its normal, monotonic increasing behavior with decreasing temperature. Magnetic fields of up to 8 kOe, either parallel or perpendicular to the unique axis of the hexagonal crystal, were applied to the sample. These decreased the absolute magnitude of the change in c33. It is thought that the acoustic wave is coupled to the spin structure by volume magnetostriction. © 1969 The American Physical Society.