THERMAL-EXPANSION OF SINGLE CRYSTALLINE CECU6

Thermal expansion of single crystalline CeCu6 has been measured in the temperature range from 7 to 200 K by using strain gauge. The effect of crystal field splittings is the largest along the b-axis and splitting energies, Δ1 and Δ2, are estimated on the basis of phenomenological theory. The thermal expansion coefficients of the b-axis αb are shown as a function of T. The αb(CeCu6) is found to increase rapidly with increasing temperature until it reaches a broad maximum around 70 K and then decreases sluggishly as T increases. On the other hand the αb (LaCu6) increases smoothly with increasing temperature and at higher temperature than 150 K the increasing rate αb becomes smaller. At 200 K, the αb is slightly larger than αb (CeCu6).