PRESSURE-TEMPERATURE-COMPOSITION PHASE DIAGRAM OF THE HEAVY FERMION COMPOUND CE2RH(1−X)IR(X)IN8 / DIAGRAMA DE FASES PRESSÃO-COMPOSIÇÃO-TEMPERATURA DO COMPOSTO FÉRMION PESADO CE2RH(1−X)IR(X)IN8

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Heavy fermion compounds behave differently from typical metals at low temperatures, where the phenomena that arise due to the correlation between conduction electrons and the f ions of the lattice become evident. An increased effective electronic mass that can reach values as high as hundreds of times the free electron mass and the coexistence of magnetic order with a superconducting state attract growing interest to these materials. When external pressure is applied on some of those systems, the antiferromagnetic transition temperature can be tuned towards absolute zero, where quantum critical fluctuations become relevant and, depending on the compound studied, an unconventional superconducting state can manifest itself. In this work, measurements of electrical resistance were made on the compounds Ce2Rh1−xIrxIn8 and the results were expressed as pressure-temperature phase diagrams for each value of x studied. Temperature-composition phase diagrams for representative pressures were also built. Two superconducting phases can be identified on the Ce2Rh1−xIrxIn8 system, one of them induced and the other supressed by applied pressure. The first one seems to be related to magnetic spin fluctuations while the second one can be related to valence fluctuations. Other interesting features can be observed on the obtained diagrams, like a possible reentrant superconducting phase at x = 0.25 and the abrupt supression of supercunductivity on values above x = 0.8.

ASSUNTO(S)

sistema eletronico electronic system supercondutividade nao-convencional unconventional superconductivity fermions pesados heavy fermions

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