Field-dependent specific heat in Fe2VAl and the question of possible 3d heavy fermion behavior

Specific heat measurements on Fe2 VAl show the previously reported upturn in electronic specific heat coefficient () to be sample dependent, and related to magnetic defects. These measurements, in temperatures as low as 0.6 K and magnetic fields up to 8 T, indicate the presence of Schottky anomalies arising from magnetic clusters having a moment 3.7B This result is in good agreement with theoretical estimates for Fe antisite defects in the material. The inherent = 1.5 0.3 mJ/molK2 deduced from this work is considerably less than previously reported, and the behavior does not appear consistent with heavy fermion behavior. However, the mass enhancement is significant when compared to nuclear magnetic resonance and band calculations, and we propose a spin-fluctuation mechanism. 1999 The American Physical Society.

Field-dependent specific heat in Fe2VAl and the question of possible 3d heavy fermion behavior Academic Article