ACOUSTIC DE HAAS-VAN-ALPHEN EFFECT OF LAB6

Acoustic de Haas-van Alphen (dHvA) effect of LaB6 has been investigate d by the ultrasonic velocity measurement. The oscillation intensities of the elastic constants have been found to be highly anisotropic even for magnetic field directions with crystallographic equivalence. This anisotropy depends strongly on the polarization and propagation direc tions of the ultrasonic modes. The observed oscillation intensities ha ve been analyzed by means of the theory of the acoustic dHvA effect wh ich bases on the effective mass approximation. These analyses enable u s to know the change of the cross-sectional areas of the Fermi surface s by the ultrasonic wave and therefore the electron-lattice interactio n. The characteristic features of the electron-lattice interactions fo r the main alpha Fermi surfaces at X points and for the small rho Ferm i surfaces on Sigma lines are presented.