Residual superconducting phases in the disordered Ce2Rh1−xIrxIn8 alloys

Abstract

We report evidence of two superconducting phases in the Ce2Rh1−xIrxIn8 heavy fermion systems. One of these phases is pressure induced and occurs for a range of compositions situated near the Rh-rich extreme, consistent with the behavior observed for the pure Ce2RhIn8 compound. This superconducting region is expanded to higher critical temperatures and lower Rh concentrations with increasing pressure. It has a clear interplay with the established antiferromagnetic state, TN∼2.8 K, suggesting that magnetic fluctuations are important for its realization. The second superconducting phase appears already at ambient pressure and it is characterized by a dome centered around x∼0.6 which, in sharp contrast with the first transition, is progressively eliminated by the application of pressure. These strikingly opposite behaviors under the same tuning parameter indicate the two transitions may have different natures. We compare these findings in the Ce2Rh1−xIrxIn8 alloys to its related CeRh1−xIrxIn5, arguing that the occurrence of the superconducting phases become unfavorable for the bilayers alloys due to higher dimensionality and stronger disorder. Further, we discuss whether the present results warrant similar claims with respect to the CeRh1−xIrxIn5 phase diagram and the possible nature of the superconducting phases.

Source-reported materials — not catalogue approval

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