Calorimetry study of the phase diagrams of EuNi2Ge2 and Eu2Ni3Ge5 under pressure

Sankaran Esakki Muthu, Daniel Braithwaite, Bernard Salce, Ai Nakamura, Masato Hedo, Takao Nakama, Yoshichika Onuki

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6 Citations (Scopus)

Abstract

We report here the phase diagrams of EuNi2Ge2 and Eu2Ni3Ge5 studied by ac calorimetry under pressure using a diamond anvil cell. We follow the antiferromagnetic transition for EuNi2Ge2 up to 1.5 GPa. The sudden disappearance of magnetic order at around 2 GPa is confirmed, consistent with the probable occurrence of a first-order valence transition near that pressure. The ac calorimetry results on Eu2Ni3Ge5 clearly show two antiferromagnetic transitions, and suggest that magnetic order persists up to higher pressure than previously expected. At high pressure, where heavy-fermion behavior has been reported, the Néel temperature is decreasing, and magnetic order is expected to disappear at an extrapolated pressure of 12-14 GPa. A semi quantitative analysis of the pressure dependence of the specific heat does not show any large changes, but is compatible with a moderate enhancement of γ. The phase diagrams of Yb and Ce heavy fermion systems are compared and discussed with our system.

Original languageEnglish
Article number094603
Journaljournal of the physical society of japan
Volume85
Issue number9
DOIs
Publication statusPublished - 2016 Sep 15
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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