Pressure effect on antiferromagnetism in CeRhIn5-xSnx studied by thermal expansion

We present low-temperature thermal expansion measurements on the Sn-substituted heavy fermion antiferromagnet CeRhIn5-xSnx for 0 ≤ x ≤ 0.36 in which TN(x) is linearly suppressed from 3.8 K at x = 0 to zero at xc ∼ 0.4. The application of the Ehrenfest relation allows to calculate the initial uniaxial and hydrostatic pressure dependences dTN/dP at various x. The observed non-linear variation with x is interpreted in terms of the Doniach diagram by an increase of the 4f-conduction electron hybridization induced by Sn-doping. As no traces of superconductivity are observed close to xc, this system is ideally suited for the study of the magnetic quantum critical point