Magneto-Acoustic Effect of Heavy Fermion Compound CeInCu2

Abstract
We measured the temperature dependences of elastic constants of the heavy fermion compound CeInCu 2 and the reference compound LaInCu 2 . The transverse C 44 and (C 11 -C 12 )/2 modes in CeInCu 2 exhibit monotonous temperature dependences. The bulk modulus C B , however, shows an anomalous softening of 6% below 130 K, which is in contrast to the normal behavior in LaInCu 2 . The anomalies of C B in CeInCu 2 indicate the coupling between the volume strain and the heavy fermion state with a large electronic Grüneisen constant Ω g ≃50 at 5 K.