Existence of Heavy Fermions in the Antiferromagnetic Phase of CeIn3

Abstract

We report the pressure-dependent optical conductivity spectra of the heavy-fermion (HF) compound CeIn 3 below the Néel temperature of 10 K to investigate the existence of the HF state in the antiferromagnetic (AFM) phase. The peak due to the interband transition in the hybridization gap between the conduction band and the nearly localized 4 f states (c-f hybridization) appears at a photon energy of about 20meV, not only in the HF regime but also in the AFM regime. Both the energy and intensity of the c-f hybridization peak continuously increase with the application of pressure from the AFM phase to the HF regime. This result suggests that c-f hybridization, as well as heavy fermions, exists even in the AFM phase of CeIn 3. © 2012 The Physical Society of Japan.