Domain Meissner state and spontaneous vortex-antivortex generation in the ferromagnetic superconductor EuFe2(As0.79P0.21)2

Vasily S Stolyarov; Ivan S Veshchunov; Sergey Yu Grebenchuk; Denis S Baranov; Igor A Golovchanskiy; Andrey G Shishkin; Nan Zhou; Zhixiang Shi; Xiaofeng Xu; Sunseng Pyon; Yue Sun; Wenhe Jiao; Guang-Han Cao; Lev Ya Vinnikov; Alexander A Golubov; Tsuyoshi Tamegai; Alexander I Buzdin; Dimitri Roditchev

doi:10.1126/sciadv.aat1061

Domain Meissner state and spontaneous vortex-antivortex generation in the ferromagnetic superconductor EuFe₂(As_0.79P_0.21)₂

Sci Adv. 2018 Jul 13;4(7):eaat1061. doi: 10.1126/sciadv.aat1061. eCollection 2018 Jul.

Authors

Vasily S Stolyarov^{1

2

3

4

5}, Ivan S Veshchunov^{1

6}, Sergey Yu Grebenchuk¹, Denis S Baranov^{1

2

7}, Igor A Golovchanskiy^{1

3}, Andrey G Shishkin^{1

2}, Nan Zhou⁸, Zhixiang Shi⁸, Xiaofeng Xu⁹, Sunseng Pyon⁶, Yue Sun^{6

10}, Wenhe Jiao¹¹, Guang-Han Cao¹¹, Lev Ya Vinnikov², Alexander A Golubov^{1

12}, Tsuyoshi Tamegai⁶, Alexander I Buzdin^{13

14}, Dimitri Roditchev⁷

Affiliations

¹ Moscow Institute of Physics and Technology (State University), Dolgoprudny, Moscow 141700, Russia.
² Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow 142432, Russia.
³ National University of Science and Technology MISiS, Moscow 119049, Russia.
⁴ Fundamental Physical and Chemical Engineering Department, Moscow State University, Moscow 119991, Russia.
⁵ Solid State Physics Department, Kazan Federal University, Kazan 420008, Russia.
⁶ Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
⁷ Laboratoire de Physique et d'Etude des Materiaux, UMR8213, École supérieure de physique et de chimie industrielles de la Ville de Paris, Paris Sciences et Lettres Research University, Institut des NanoSciences de Paris-Sorbonne Universite, 10 rue Vauquelin, 75005 Paris, France.
⁸ School of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189, China.
⁹ Department of Physics, Changshu Institute of Technology, Changshu 215500, China.
¹⁰ Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan.
¹¹ Department of Physics, Zhejiang University, Hangzhou 310027, China.
¹² Faculty of Science and Technology and MESA+ Institute of Nanotechnology, University of Twente, 7500 AE Enschede, Netherlands.
¹³ University Bordeaux, Laboratoire Ondes et Matière d'Aquitaine, F-33405 Talence, France.
¹⁴ Department of Materials Science and Metallurgy, University of Cambridge, CB3 0FS Cambridge, UK.

Abstract

The interplay between superconductivity and magnetism is one of the oldest enigmas in physics. Usually, the strong exchange field of ferromagnet suppresses singlet superconductivity via the paramagnetic effect. In EuFe₂(As_0.79P_0.21)₂, a material that becomes not only superconducting at 24.2 K but also ferromagnetic below 19 K, the coexistence of the two antagonistic phenomena becomes possible because of the unusually weak exchange field produced by the Eu subsystem. We demonstrate experimentally and theoretically that when the ferromagnetism adds to superconductivity, the Meissner state becomes spontaneously inhomogeneous, characterized by a nanometer-scale striped domain structure. At yet lower temperature and without any externally applied magnetic field, the system locally generates quantum vortex-antivortex pairs and undergoes a phase transition into a domain vortex-antivortex state characterized by much larger domains and peculiar Turing-like patterns. We develop a quantitative theory of this phenomenon and put forth a new way to realize superconducting superlattices and control the vortex motion in ferromagnetic superconductors by tuning magnetic domains-unprecedented opportunity to consider for advanced superconducting hybrids.

Publication types

Research Support, Non-U.S. Gov't