New Magnetic State in Incommensurate Magnetic Phase of Heavy-Fermion Superconductor CeRh0.6Co0.4In5

TL;DR

This study reveals a new commensurate antiferromagnetic order in CeRh0.6Co0.4In5 near a quantum critical point, showing how magnetic correlations evolve and potentially relate to superconductivity in heavy-fermion materials.

Contribution

It uncovers a novel commensurate magnetic phase in CeRh0.6Co0.4In5 and links magnetic order evolution to superconductivity near a quantum critical point.

Findings

Incommensurate AF order persists below 3.5 K.

A new commensurate AF order appears below 2.9 K.

Magnetic moments are reduced compared to pure CeRhIn5.

Abstract

We performed elastic neutron scattering experiments on solid solution CeRh1-xCoxIn5 with x=0.4 to clarify the nature of the antiferromagnetic (AF) phase in the vicinity of the quantum critical point. We observed the incommensurate AF order below T_Nh=3.5 K. The structure of the incommensurate AF order is basically unchanged from that for pure CeRhIn5. We further found the evolution of a new commensurate AF order with the modulation of q_c=(1/2,1/2,1/2) below T_Nc=2.9 K. The volume-averaged moments for the incommensurate and commensurate AF phases are 0.38 mu_B/Ce and 0.21 mu_B/Ce, respectively, which are reduced from the incommensurate AF moment (0.75 mu_B/Ce) for pure CeRhIn5. We suggest from these results that the commensurate magnetic correlation may be tightly coupled with the superconductivity observed below T_c=1.4 K.