Anomalous upper critical field in the heavy-fermion superconductor UBe 13 studied by DC magnetization measurements

Yusei Shimizu, Yoshinori Haga, Kenichi Tenya, Tatsuya Yanagisawa, Hiroyuki Hidaka, Hiroshi Amitsuka

Research output: Contribution to journalConference articlepeer-review

2 Citations (Scopus)


We have studied anomalous upper critical field Bc2(T) of a single crystal of UBe13 by DC magnetization measurements down to 0.14 K and up to 8 T. We have observed a broad anomaly and a peak effect below Bc2 in magnetization curves. Although a possibility of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state has been proposed as an origin of the unusual upper critical field by previous works, our results have shown that thermal equilibrium magnetization curves reveal no step-like behavior, which could be observed at 1st-order phase transition from a superconducting mixed state to the FFLO state. We have also investigated anisotropy of Bc2 for B || <001> and B || <110>, and found that Bc2 for B || <001< is larger than Bc2 for B || <110> below ∼ 0.5 K. These results might indicate that the anomalous upward curvature of Bc2 in UBe13 is related to anisotropy of Bc2 rather than the FFLO state.

Original languageEnglish
Article number012065
JournalJournal of Physics: Conference Series
Issue number1
Publication statusPublished - 2012
Externally publishedYes
EventInternational Conference on Strongly Correlated Electron Systems, SCES 2011 - Cambridge, United Kingdom
Duration: 2011 Aug 292011 Sep 3

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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