TEMPERATURE DEPENDENCE OF THE ELASTIC MODULI OF POLYCRYSTALLINE ZrZn₂.

The longitudinal and transversal sound velocities in the weak itinerant ferromagnet ZrZn//2 have been measured as function of temperature between 10 and 300 degree K. The temperature dependence of the Young and shear moduli, the Debye temperature, and the adiabatic compressibility are calculated. Two anomalies are observed: one at 220 degree K, which may be accounted for by the anisotropic d-band structure of ZrZn//2, the second, at 45 degree K suggesting a first-order phase transition the nature of which is not yet understood. No significant change in the elastic moduli is observed at the Curie temperature.