Occurrence of magnetism in CeMIn5-xHgx (M = Rh, Ir)

The physical properties of CeM(In1-xHgx)(5) (M = Rh, Ir) including specific heat and magnetic susceptibility are reported. Two magnetic phases exist in CeRhIn(In1-xHgx)(5) with some evidence of a change from incommensurate magnetic order to a commensurate structure near 10% nominal Hg substitution. In CeIr(In1-xHgx)(5), an antiferromagnetic quantum critical point near x = 3% (followed by robust long-range antiferromagnetism for x > 5%) appears to be separated from superconductivity in CeIrIn5. The multitude of magnetic ground states observed in the CeM(In1-xHgx)(5) Materials is quite sensitive to doping and magnetic fields. (C) 2007 Published by Elsevier B.V.