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Semináře

 
Title: Daniel Braithwaite: UTe2: Excitement along the road of heavy fermion superconductivity
Number: 20/20
Status: Closing date exceeded
Begin: Středa, 14.10. 2020, 14:10
Tutor: Vladimír Sechovský
Location: ZOOM Meeting ID: 958 0426 7376
Files:
Abstract_Braithwaite.pdfAbstract


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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

 

UTe2: Excitement along the road of heavy fermion superconductivity

lecture given by:

Daniel Braithwaite

Univ. Grenoble Alpes, CEA, IRIG-PHELIQS, 38000 Grenoble, France

 

https://cesnet.zoom.us/j/95804267376
Meeting ID: 958 0426 7376 

on Wednesday, 14.10. 2020 from 14:10 CEST (12.10 UTC) 


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Vladimír Sechovský
On behalf of the DCMP and MGML


Abstract 

Unconventional superconductivity was first discovered in heavy fermion systems 40 years ago. Today this field for research is constantly yielding new information and surprises. One particularly fruitful branch is the family of uranium based ferromagnetic superconductors, which have brought the decisive proof of the role of magnetic fluctuations in the superconducting pairing mechanism, as well as harboring such rare phenomena as a probable triplet “p-wave” superconducting order parameter and an enhancement of superconductivity by an external magnetic field. This latter spectacular effect was qualitatively understood by the destabilization of ferromagnetic order when a field is applied transverse to the direction of the ordered moments in these Ising type systems, leading to a new channel of magnetic fluctuations boosting superconductivity. This picture was however recently challenged by the discovery of superconductivity with a similar enhancement under magnetic field in the paramagnetic heavy fermion system UTe2. Over the past year UTe2 has been the subject of intense research by teams in the US, Japan and France. I will present some of the recent results including reinforced or re-entrant superconductivity under applied field, metamagnetism, as well as the surprising behavior under pressure where the superconducting critical temperature is enhanced by a factor 2, reaching 3K, and the rare phenomenon of multiple superconducting phases is found.

db1 db2

Left figure shows the phase diagram of UTe2 under magnetic field applied along the b-axis.

 

Right figure shows the phase diagram of UTe2 under hydrostatic pressure. SC1 and SC2 are 2 different superconducting phases. MO indicates probable magnetic order.