Linear temperature dependence of the electric quadrupole interaction of111Cd impurities in holmium

The electric quadrupole interaction of¹¹¹Cd impurities in metallic holmium has been investigated between 140 K and 655 K by time differential perturbed angular correlation measurements. The quadrupole frequency decreases with increasing temperature. This decrease is a linear function of temperature, in contrast to theT^3/2 dependence usually observed in non-cubic metals. Possible reasons for the deviation from theT^3/2 relation are discussed.