Elastic anomalies and acoustic quantum oscillation in CeCo2

Elastic properties of CeCo2 single crystals have been investigated It has b een found that CeCo2 shows a remarkable elastic softening in c(44) and (c(1 1)-c(12))/2. The elastic anomaly suggests a very narrow band of 149 K. Acou stic quantum oscillation has been successfully observed in CeCo2. The measu rement by using He-3-He-4 dilution refrigerator gave us the effective mass of kappa-Orbit. The quantum oscillation frequency and the value of the effe ctive mass are 193 T and 1.17m(0). and 232 T and 1.73m(0) for the magnetic field directions parallel to [1 0 0] and [1 1 0], respectively. (C) 2000 El sevier Science B.V. All rights reserved.