Temperature and Magnetic Field Dependence of Elastic Constants in (La, Ce)B₆ Single Crystals

Abstract

Measurements of the sound velocity in dilute (La1-xCex)B6 (x=0.01,0.03,0.1) crystals were used to determine the temperature and magnetic field dependence of elastic constants c44 and (c11-c12)/2. Their softening below 4.2 K is explained on the basis of a single ion magnetoelastic interaction. From this we conclude that the majority of Ce-ions has static splitting (2.2 K) of the Γ8 ground state into two doublets. From the observed magnetoacoustic quantum oscillations in very dilute (La,Ce)B6 Fermi surface cross sections, effective Dingle temperatures and their T-dependence were determined.