MGML

Materials Growth & Measurement Laboratory

Jun Gouchi: Pressure effect on the complex phase diagram of heavy-fermion superconductor UPt3

Seminar on Magnetism
Date: Wednesday, 28 August 2019 14:00 - 15:00

Venue: lecture room F2, first floor, Ke Karlovu 5 - Prague 2


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We have a pleasure to invite you to attend the joint seminar
of the Department of Condensed Matter Physics (DCMP)
and the Materials Growth and Measurement Laboratory (MGML) http://mgml.eu.

 

Program

 

Pressure effect on the complex phase diagram of heavy-fermion superconductor UPt3

lecture given by:

Jun Gouchi

 

Institute for Solid State Physics, The University of Tokyo, Japan

The seminar takes place in the lecture room F2 
of the Faculty of Mathematics and Physics, Ke Karlovu 5, Praha 2
on Wednesday, 28.8. 2019 from 14:10 

Vladimír Sechovský
On behalf of the DCMP and MGML


Abstract 

The heavy-fermion superconductor UPt3 is one of the famous unconventional superconductors. It is known to be in an odd-parity pairing state, which has a complex field - temperature phase diagram [1]. Two favorable candidates: pairing function E2u [2] and E1u scenarios [3] have been proposed. These scenarios are still controversial.

Josephson effect is very sensitive to the phase and spin state of the order parameter. For example, anisotropic temperature dependence of Josephson critical current have been observed at the transition from A to B of superconducting phase [4]. Whether superconducting state is a time-reversal symmetry breaking (TRSB) which can be clarified from field dependence of measurements.

In our researches, superconducting states of UPt3 is not BTRS [5]. The superconducting state at ambient pressure can be explained by E1u scenario. In the tri-critical point of UPt3 under pressure, the Meissner fraction at 0.2 K reaches a minimum value at . and the penetration depth decrease. These results suggest that the superconducting phase is modified above .[6].

Recent development of the ISSP high-pressure labs about two-stage multi anvil apparatus generating pressure over 20 GPa and specially designed the clamp type Palm CAC working down to 10 mK and magnetic field 9 T will be introduced.

  • [1] G. Bruls et al. Phys. Rev. Lett. 65 2294 (1990).
  • [2] J. A. Sauls J. Low Temp. Phys. 95, 153 (1994).
  • [3] Y. Machida et al. Phys. Rev. Lett. 108, 157002 (2012).
  • [4] A. Sumiyama et al. Phys. Rev. Lett. 81, 5213 (1998).
  • [5] J. Gouchi et al. J. Phys. Soc. Jpn. 81, 113701 (2012).
  • [6] J. Gouchi et al. Phys. Rev. B 93, 174514 (2016).

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All Dates


  • Wednesday, 28 August 2019 14:00 - 15:00