{"id":8639,"date":"2020-03-26T10:50:00","date_gmt":"2020-03-26T08:50:00","guid":{"rendered":"https:\/\/lncmi.cnrs.fr\/?p=8639"},"modified":"2025-07-07T13:52:21","modified_gmt":"2025-07-07T11:52:21","slug":"magnetic-field-induced-metamagnetism-and-superconductivity-in-ute2","status":"publish","type":"post","link":"https:\/\/lncmi.cnrs.fr\/en\/news\/magnetic-field-induced-metamagnetism-and-superconductivity-in-ute2\/","title":{"rendered":"Magnetic field induced metamagnetism and superconductivity in UTe2"},"content":{"rendered":"\n

Following the recent discovery of superconductivity in the heavy-fermion paramagnet UTe2<\/sub>, which is suspected to lie on the verge of ferromagnetism [S. Ran et al., arXiv:1811.11808v3, D. Aoki et al., J. Phys. Soc. Jpn. 88 (2019) 043702], complementary and almost simultaneous series of magnetoresistivity experiments on UTe2 <\/sub>were performed in steady fields up to 35 T at LNCMI Grenoble and in pulsed fields up to 70 T at LNCMI Toulouse.<\/p>\n\n\n\n

As step one, low-temperature metamagnetism was evidenced in a magnetic field applied along the hard magnetic b axis at \u00b50<\/sub>Hm<\/sub> = 35 T (Figure, left). When the temperature is raised, a signature of first-order metamagnetism was observed up to a critical endpoint at 7 K. A sharp maximum in the quadratic Fermi-liquid coefficient of the resistivity found at Hm<\/sub> indicates an enhanced effective mass associated with critical magnetic fluctuations, possibly coupled with a Fermi-surface instability.<\/p>\n\n\n\n

As step two, we have discovered that low-temperature superconductivity is reinforced when Hm<\/sub> is approached in a field applied along b, and suddenly disappears above Hm<\/sub> (Figure, right). A home-made dilution refrigerator specially developed for the pulsed-field experiments at LNCMI Toulouse was used. By studying the angular dependence of the superconducting upper critical field in field directions close to the b axis, <\/sub>the maximum of the reentrant superconducting temperature was found to be rapidly depinned from the metamagnetic field. A key ingredient for the field reinforcement of superconductivity on approaching Hm<\/sub> appears to be an immediate interplay with magnetic fluctuations and a possible Fermi-surface reconstruction. Further studies of the field-induced superconductivity in UTe2<\/sub> are now planned at LNCMI.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Figure: Signatures of (left) high-temperature metamagnetism and (right) low-temperature superconductivity in the electrical resistivity of UTe2<\/sub> in a magnetic field applied along the crystallographic b axis.<\/p>\n\n\n\n

Publications – Magnetic-field-induced phenomena in the paramagnetic superconductor UTe2
<\/strong>W. Knafo, M. Valiska, D. Braithwaite, G. Lapertot, G. Knebel, A. Pourret, J.-P. Brison, J. Flouquet, and D. Aoki, J. Phys. Soc. Jpn. 88<\/strong>, 063705 (2019)<\/a><\/p>\n\n\n\n

Field-reentrant superconductivity close to a metamagnetic transition in the heavy-fermion superconductor UTe2
<\/strong>G. Knebel, W. Knafo, A. Pourret, Q. Niu, M. Valiska, D. Braithwaite, G. Lapertot, M. Nardone, A. Zitouni, S. Mishra, I. Sheikin, G. Seyfarth, J.-P. Brison, D. Aoki, and J. Flouquet, J. Phys. Soc. Jpn. 88<\/strong>, 063707 (2019).<\/a><\/p>\n\n\n\n

Contact: W. Knafo, I. Sheikin, G. Seyfarth<\/p>\n","protected":false},"excerpt":{"rendered":"

Following the recent discovery of superconductivity in the heavy-fermion paramagnet UTe2, which is suspected to lie on the verge of ferromagnetism [S. Ran et al., arXiv:1811.11808v3, D. Aoki et al., […]<\/p>\n","protected":false},"author":1,"featured_media":23337,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[292],"tags":[],"post_folder":[],"class_list":["post-8639","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"jetpack_featured_media_url":"https:\/\/lncmi.cnrs.fr\/wp-content\/uploads\/2020\/03\/New1.png","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/lncmi.cnrs.fr\/en\/wp-json\/wp\/v2\/posts\/8639","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lncmi.cnrs.fr\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lncmi.cnrs.fr\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lncmi.cnrs.fr\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lncmi.cnrs.fr\/en\/wp-json\/wp\/v2\/comments?post=8639"}],"version-history":[{"count":0,"href":"https:\/\/lncmi.cnrs.fr\/en\/wp-json\/wp\/v2\/posts\/8639\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/lncmi.cnrs.fr\/en\/wp-json\/wp\/v2\/media\/23337"}],"wp:attachment":[{"href":"https:\/\/lncmi.cnrs.fr\/en\/wp-json\/wp\/v2\/media?parent=8639"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lncmi.cnrs.fr\/en\/wp-json\/wp\/v2\/categories?post=8639"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lncmi.cnrs.fr\/en\/wp-json\/wp\/v2\/tags?post=8639"},{"taxonomy":"post_folder","embeddable":true,"href":"https:\/\/lncmi.cnrs.fr\/en\/wp-json\/wp\/v2\/post_folder?post=8639"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}