Unique interplay between superconducting and ferromagnetic orders in EuRbFe4As4

V. S. Stolyarov; A. Casano; M. A. Belyanchikov; A. S. Astrakhantseva; S. Yu. Grebenchuk; D. S. Baranov; I. A. Golovchanskiy; I. Voloshenko; E. S. Zhukova; B. P. Gorshunov; A. V. Muratov; V. V. Dremov; L. Ya. Vinnikov; D. Roditchev; Y. Liu; G.-H. Cao; M. Dressel; E. Uykur

doi:10.1103/PhysRevB.98.140506

Unique interplay between superconducting and ferromagnetic orders in EuRbFe4As4

V. S. Stolyarov, A. Casano, M. A. Belyanchikov, A. S. Astrakhantseva, S. Yu. Grebenchuk, D. S. Baranov, I. A. Golovchanskiy, I. Voloshenko, E. S. Zhukova, B. P. Gorshunov, A. V. Muratov, V. V. Dremov, L. Ya. Vinnikov, D. Roditchev, Y. Liu, G.-H. Cao, M. Dressel, E. Uykur

DOI 10.1103/PhysRevB.98.140506 · Physical Review B

T1

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Abstract

Transport, magnetic, and optical investigations on EuRbFe4As4 single crystals evidence that the ferromagnetic ordering of the Eu2+ magnetic moments at Tm=15 K, below the superconducting transition (Tc=36 K), affects superconductivity in a weak but intriguing way. Upon cooling below Tm, the zero resistance state is preserved and the diamagnetic response is only slightly affected by the emerging ferromagnetism; a perfect diamagnetism is recovered at low temperatures. The infrared conductivity is strongly suppressed in the far-infrared region below Tc, associated with the opening of a complete superconducting gap at 2Δ=10 meV. A gap smaller than the weak-coupling limit suggests strong orbital effects or, within a multiband superconductivity scenario, the existence of a larger yet unrevealed gap.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
EuRbFe4As4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	36.25	Pressure not reported	onset
EuRbFe4As4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	36	Pressure not reported	onset
EuFe2As2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
CaKFe4As4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	31	Pressure not reported	unknown