Vanishing ferromagnetism and sharp valence-crossover in CePd1-xRhx under high-pressure

PEDRAZZINI, P.; JACCARD, D.; DEPPE, M.; GEIBEL, C.; SERENI, J.G.

Buzios

Conferencia; International Conference on Strongly Correlated Electron Systems SCES-2008; 2008

Centro Brasileiro de Pesquisas Físicas (CBPF), Universidade Federal Fluminense (UFF)

Ferromagnetic Ce-compounds are far less abundant than antiferromagnetic ones and thus, the critical region of such systems has been scarcely studied. An analysis of reported results suggests that in most clean cases, ferromagnetism is suppressed at a finite temperature critical end point. Alloying could smear out the first order phase transition resulting in a continuous disappearance of magnetism. We present the results of a recent multiprobe high-pressure experiment performed on a single crystal ofthe ferromagnetic alloy CePd 1-x Rh x , with x=0.4. From the analysis of simultaneous resistivity, thermopower and ac-heat-capacity measurements we argue that long-range ferromagnetism vanishes in the proximity of a sharp valence-crossover pressure p V ≈7.5 GPa, i.e. before reaching a T C (p)=0 quantum critical point. However, a magnetic signal that is progressively suppressed is still detected at higher pressures. We compare these results with the measurements on the CePd1-xRhx alloy and with other pressurized ferromagnets. Furthermore, we discuss some of the advantages of such multiprobe experiments.